Use asm/unaligned.h instead of linux/unaligned/access_ok.h header file to
fix compiling issues such as following while doing cross platform
compiling:

"include/linux/unaligned/access_ok.h:7:19: error: redefinition of
 'get_unaligned_le16'
...
include/linux/unaligned/le_struct.h:6:19: note: previous definition of
 'get_unaligned_le16' was here".
Reported-by: kbuild test robot <kbuild-all@01.org>
Signed-off-by: Dudley Du <dudl@cypress.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>