Fix up ARM serial driver compile failure

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Acked-by: David S. Miller <[e-mail]>
Acked-by: Russell King <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/serial_core.h

···
 #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...