[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>

arch/arm/Kconfig

@@ -69,6 +69,9 @@ config GENERIC_ISA_DMA
 config FIQ
 	bool
 
+config ARCH_MTD_XIP
+	bool
+
 source "init/Kconfig"
 
 menu "System Type"
@@ -136,6 +139,7 @@ config ARCH_L7200
 
 config ARCH_PXA
 	bool "PXA2xx-based"
+	select ARCH_MTD_XIP
 
 config ARCH_RPC
 	bool "RiscPC"
@@ -152,6 +156,7 @@ config ARCH_SA1100
 	bool "SA1100-based"
 	select ISA
 	select ARCH_DISCONTIGMEM_ENABLE
+	select ARCH_MTD_XIP
 
 config ARCH_S3C2410
 	bool "Samsung S3C2410"

drivers/mtd/chips/Kconfig

@@ -301,7 +301,7 @@ config MTD_JEDEC
 
 config MTD_XIP
 	bool "XIP aware MTD support"
-	depends on !SMP && (MTD_CFI_INTELEXT || MTD_CFI_AMDSTD) && EXPERIMENTAL && ARM
+	depends on !SMP && (MTD_CFI_INTELEXT || MTD_CFI_AMDSTD) && EXPERIMENTAL && ARCH_MTD_XIP
 	default y if XIP_KERNEL
 	help
 	  This allows MTD support to work with flash memory which is also