dmi: Avoid unaligned memory access in save_mem_devices()

Firmware is not required to maintain alignment of SMBIOS
entries, so we should take care accessing fields within these
structures. Use "get_unaligned()" to avoid problems.

[ Found on ia64 (which grumbles about unaligned access) ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/27d82dbff5be1025bf18ab88498632d36c2fcf3c.1383331440.git.tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>