If the kernel config 'CONFIG_ALIGNMENT_TRAP' and the file
'/proc/sys/nds32/unaligned_access/enable' are set, the kernel
unaligned access handler does not handle correctly when the
value of immediate field is negative. This commit fixes the
unaligned access handler in kernel.
Signed-off-by: Nickhu <nickhu@andestech.com> Reviewed-by: Greentime Hu <greentime@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com>