riscom8: fix SMP brokenness

After analyzing the elements that save_flags/cli/sti/restore_flags were
protecting, convert their usages to a global spinlock (the easiest and
most obvious next-step).  There were some usages of flags being
intentionally cached, because the code already knew the state of
interrupts.  These have been taken into account.

This allows us to remove CONFIG_BROKEN_ON_SMP.  Completely untested.

[akpm@linux-foundation.org: use DEFINE_SPINLOCK]
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/Kconfig

@@ -276,7 +276,7 @@ config N_HDLC
 
 config RISCOM8
 	tristate "SDL RISCom/8 card support"
-	depends on SERIAL_NONSTANDARD && BROKEN_ON_SMP
+	depends on SERIAL_NONSTANDARD
 	help
 	  This is a driver for the SDL Communications RISCom/8 multiport card,
 	  which gives you many serial ports. You would need something like