ARM: Allow kernel unaligned accesses on ARMv6+ processors

Recent gcc versions generate unaligned accesses by default on ARMv6 and
later processors. This patch ensures that the SCTLR.A bit is always
cleared on such processors to avoid kernel traping before
alignment_init() is called.

Change-Id: I2666c83b89c476b56387ca1ab3947bf88c4af432
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>