[PATCH] arm: fix dependencies for MTD_XIP

MTD_XIP depends on having working asm/mtd-xip.h; it's not just per-architecture
(arm-only, as current Kconfig would have it), but actually per-subarch as
well.  Introduced a new symbol (ARCH_MTD_XIP) set by arch Kconfig; MTD_XIP
depends on it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5959e36..4a63a8e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -69,6 +69,9 @@
 config FIQ
 	bool
 
+config ARCH_MTD_XIP
+	bool
+
 source "init/Kconfig"
 
 menu "System Type"
@@ -136,6 +139,7 @@
 
 config ARCH_PXA
 	bool "PXA2xx-based"
+	select ARCH_MTD_XIP
 
 config ARCH_RPC
 	bool "RiscPC"
@@ -152,6 +156,7 @@
 	bool "SA1100-based"
 	select ISA
 	select ARCH_DISCONTIGMEM_ENABLE
+	select ARCH_MTD_XIP
 
 config ARCH_S3C2410
 	bool "Samsung S3C2410"