Revert "MIPS: SiByte: Enable swiotlb for SWARM, LittleSur and BigSur"

This reverts commit 8ac4ad063e1a32e321a7a0e6ea9fd305a6ecd033 which is
commit e4849aff1e169b86c561738daf8ff020e9de1011 upstream

Guenter writes:
	Upstream commit e4849aff1e16 ("MIPS: SiByte: Enable swiotlb for SWARM,
	LittleSur and BigSur") results in build failures in v4.4.y and v4.14.y.

	make bigsur_defconfig:

	warning: (SIBYTE_SWARM && SIBYTE_SENTOSA && SIBYTE_BIGSUR && SWIOTLB_XEN && AMD_IOMMU) selects SWIOTLB which has unmet direct dependencies (CAVIUM_OCTEON_SOC || MACH_LOONGSON64 && CPU_LOONGSON3 || NLM_XLP_BOARD || NLM_XLR_BOARD)
	warning: (SIBYTE_SWARM && SIBYTE_SENTOSA && SIBYTE_BIGSUR && SWIOTLB_XEN && AMD_IOMMU) selects SWIOTLB which has unmet direct dependencies (CAVIUM_OCTEON_SOC || MACH_LOONGSON64 && CPU_LOONGSON3 || NLM_XLP_BOARD || NLM_XLR_BOARD)

	and the actual build:

	lib/swiotlb.o: In function `swiotlb_tbl_map_single':
	(.text+0x1c0): undefined reference to `iommu_is_span_boundary'
	Makefile:1021: recipe for target 'vmlinux' failed

Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 6cd2304..92bcde0 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -792,7 +792,6 @@
 	select SYS_SUPPORTS_HIGHMEM
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select ZONE_DMA32 if 64BIT
-	select SWIOTLB if ARCH_DMA_ADDR_T_64BIT && PCI
 
 config SIBYTE_LITTLESUR
 	bool "Sibyte BCM91250C2-LittleSur"
@@ -815,7 +814,6 @@
 	select SYS_HAS_CPU_SB1
 	select SYS_SUPPORTS_BIG_ENDIAN
 	select SYS_SUPPORTS_LITTLE_ENDIAN
-	select SWIOTLB if ARCH_DMA_ADDR_T_64BIT && PCI
 
 config SIBYTE_BIGSUR
 	bool "Sibyte BCM91480B-BigSur"
@@ -829,7 +827,6 @@
 	select SYS_SUPPORTS_HIGHMEM
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select ZONE_DMA32 if 64BIT
-	select SWIOTLB if ARCH_DMA_ADDR_T_64BIT && PCI
 
 config SNI_RM
 	bool "SNI RM200/300/400"
diff --git a/arch/mips/sibyte/common/Makefile b/arch/mips/sibyte/common/Makefile
index 3ef3fb6..b3d6bf2 100644
--- a/arch/mips/sibyte/common/Makefile
+++ b/arch/mips/sibyte/common/Makefile
@@ -1,5 +1,4 @@
 obj-y := cfe.o
-obj-$(CONFIG_SWIOTLB)			+= dma.o
 obj-$(CONFIG_SIBYTE_BUS_WATCHER)	+= bus_watcher.o
 obj-$(CONFIG_SIBYTE_CFE_CONSOLE)	+= cfe_console.o
 obj-$(CONFIG_SIBYTE_TBPROF)		+= sb_tbprof.o
diff --git a/arch/mips/sibyte/common/dma.c b/arch/mips/sibyte/common/dma.c
deleted file mode 100644
index eb47a94..0000000
--- a/arch/mips/sibyte/common/dma.c
+++ /dev/null
@@ -1,14 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- *	DMA support for Broadcom SiByte platforms.
- *
- *	Copyright (c) 2018  Maciej W. Rozycki
- */
-
-#include <linux/swiotlb.h>
-#include <asm/bootinfo.h>
-
-void __init plat_swiotlb_setup(void)
-{
-	swiotlb_init(1);
-}