arch: define the ARCH_DMA_ADDR_T_64BIT config symbol in lib/Kconfig

Define this symbol if the architecture either uses 64-bit pointers or the
PHYS_ADDR_T_64BIT is set.  This covers 95% of the old arch magic.  We only
need an additional select for Xen on ARM (why anyway?), and we now always
set ARCH_DMA_ADDR_T_64BIT on mips boards with 64-bit physical addressing
instead of only doing it when highmem is set.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: James Hogan <jhogan@kernel.org>

arch/arm/mach-shmobile/Kconfig

@@ -29,7 +29,6 @@ config ARCH_RMOBILE
 menuconfig ARCH_RENESAS
 	bool "Renesas ARM SoCs"
 	depends on ARCH_MULTI_V7 && MMU
-	select ARCH_DMA_ADDR_T_64BIT if ARM_LPAE
 	select ARCH_SHMOBILE
 	select ARM_GIC
 	select GPIOLIB