Not all architectures implement asm/serial.h, and the driver doesn't appear to
need it anyway.
Cc: Paul Fulghum <paulkf@microgate.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>