arm64: cache: change ARCH_DMA_MINALIGN and L1_CACHE_SHIFT values

This reverts commit 2f1c2747
and also sets ARM_DMA_MINALIGN to 128.
ARCH_DMA_MINALIGN is dependent on L1_CACHE_SHIFT but it should
be set to maximum *known* cache line size on ARMv8 systems to
avoid DMA coherecy issues. So setting ARM_DMA_MINALIGN to 128.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Change-Id: I3fcdba32d0bf574f0af7c924ae926dd47df75e07
Patch-mainline: linux-kernel @ 21/03/16, 17:14:03
Signed-off-by: Imran Khan <kimran@codeaurora.org>