arch: hexagon: Kconfig: add HAVE_DMA_ATTR in Kconfig and remove "linux/dma-mapping.h" from "asm/dma-mapping.h"

When HAS_DMA, and also need use generic implementation, HAVE_DMA_ATTR
must be enabled, or can not pass compiling with allmodconfig, the
related error:

    CC [M]  drivers/ata/libata-core.o
  drivers/ata/libata-core.c: In function 'ata_sg_clean':
  drivers/ata/libata-core.c:4598:3: error: implicit declaration of function 'dma_unmap_sg' [-Werror=implicit-function-declaration]
  drivers/ata/libata-core.c: In function 'ata_sg_setup':
  drivers/ata/libata-core.c:4708:2: error: implicit declaration of function 'dma_map_sg' [-Werror=implicit-function-declaration]

"linux/dma-mapping.h" will include "asm/dma-mapping.h", so need remove
"linux/dma-mapping.h" from "asm/dma-mapping.h",

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index 09df260..fbc5c78 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -28,6 +28,7 @@
 	select GENERIC_CLOCKEVENTS_BROADCAST
 	select MODULES_USE_ELF_RELA
 	select GENERIC_CPU_DEVICES
+	select HAVE_DMA_ATTRS
 	---help---
 	  Qualcomm Hexagon is a processor architecture designed for high
 	  performance and low power across a wide variety of applications.