m68knommu: fix coldfire tcdrain

Fix tcdrain on coldfire uarts.
Currently with coldfire uarts tcdrain returns without waiting for txempty,
because (tx)fifosize is 0.  Fix that and call uart_update_timeout when
setting the baud rate, otherwise tcdrain will wait for an half our :)
Also constify mcf_uart_ops.

Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
diff --git a/arch/m68k/include/asm/mcfuart.h b/arch/m68k/include/asm/mcfuart.h
index ef22938..01a8716 100644
--- a/arch/m68k/include/asm/mcfuart.h
+++ b/arch/m68k/include/asm/mcfuart.h
@@ -212,5 +212,10 @@
 #define	MCFUART_URF_RXS		0xc0		/* Receiver status */
 #endif
 
+#if defined(CONFIG_M5272)
+#define MCFUART_TXFIFOSIZE	25
+#else
+#define MCFUART_TXFIFOSIZE	1
+#endif
 /****************************************************************************/
 #endif	/* mcfuart_h */