drivers: soc: ramdump: Ensure aligned addresses are passed to copy_to_user

ARMV8 architectures do not allow misaligned accesses
to device memory. Until an implementation of copy_to_user
that respects this requirement is available, ensure
that aligned addresses are passed in to copy_to_user.

Change-Id: Iea509094fe3f915310b50a471a467226a68460a2
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>