[PATCH] Char: mxser_new, revert spin_lock changes

Some spinlock changes were introduced in 1.9.1 original moxa driver.  Revert
them, since they cause machine not responding.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>