Fix up ARM serial driver compile failure

Proud member of Uglyhacks'R'US.
Acked-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NRussell King <rmk+lkml@arm.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

include/linux/serial_core.h

@@ -401,6 +401,9 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch,
 #endif
 	return 0;
 }
+#ifndef SUPPORT_SYSRQ
+#define uart_handle_sysrq_char(port,ch,regs) uart_handle_sysrq_char(port, 0, NULL)
+#endif
 
 /*
  * We do the SysRQ and SAK checking like this...