xtensa: move invalid unaligned instruction handler closer to its users

With this change a threaded jump from .Linvalid_instruction_load to
.Linvalid_instruction can be removed and more code may be added to
common load/store exit path.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

diff --cc arch/xtensa/kernel/align.S
Simple merge