serial: 8250: Decouple RSA probe

Prepare for 8250 split; separate RSA probe and resource management
from base port operations. Override base port operations for the
config_port(), request_port() and release_port() methods to
implement the optional RSA probe and resource management only in
the universal/legacy 8250 driver.

Introduce 'probe' flags for 8250 ports, which allows drivers higher
up the driver stack to enable optional probes.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 50735a9..78097e7 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -102,6 +102,8 @@
 	unsigned char		canary;		/* non-zero during system sleep
 						 *   if no_console_suspend
 						 */
+	unsigned char		probe;
+#define UART_PROBE_RSA	(1 << 0)
 
 	/*
 	 * Some bits in registers are cleared on a read, so they must