staging: sb105x: clean up interface type test

IIR_RS232 is zero so "if (IIR_RS232 == (b_ret & IIR_RS232))" is always
true so RS232 was always chosen by default.  The test should be
"if (0 == (b_ret & 0x30)) { ".  The other tests should also be in that
format.

This does change how the code works...  If 0x30 is set then it now
defaults to RS232 instead of RS485.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/sb105x/sb_mp_register.h

@@ -45,7 +45,7 @@
 #define IIR_RS232		0x00		/* RS232 type */
 #define IIR_RS422		0x10		/* RS422 type */
 #define IIR_RS485		0x20		/* RS485 type */
-#define IIR_UNKNOWN		0x30		/* unknown type */
+#define IIR_TYPE_MASK		0x30
 
 /* Interrrupt Mask Register */
 #define MP_OPTR_IMR0		0x0C 	/* port0 ~ port8 */

drivers/staging/sb105x/sb_pci_mp.c

@@ -2851,18 +2851,12 @@ static void __init multi_init_ports(void)
 				printk("IIR_RET = %x\n",b_ret);
 			}
 
-			if(IIR_RS232 == (b_ret & IIR_RS232))
-			{
-				mtpt->interface = RS232;
-			}
-			if(IIR_RS422 == (b_ret & IIR_RS422))
-			{
+			/* default to RS232 */
+			mtpt->interface = RS232;
+			if (IIR_RS422 == (b_ret & IIR_TYPE_MASK))
 				mtpt->interface = RS422PTP;
-			}
-			if(IIR_RS485 == (b_ret & IIR_RS485))
-			{
+			if (IIR_RS485 == (b_ret & IIR_TYPE_MASK))
 				mtpt->interface = RS485NE;
-			}
 		}
 	}
 }