beagleboard: remove RevB support for BeagleBoard Xm

As reported in http://marc.info/?l=u-boot&m=137358037827735&w=2

There is no need for the "xMB" variant, as the gpio pins used for
identification where never changed from the xMA when the newer silcon
was used for the xMB, So rename XM A revision as AB revision
and report accordingly

Reported-by: Robert Nelson <robertcnelson@gmail.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
diff --git a/board/ti/beagle/beagle.c b/board/ti/beagle/beagle.c
index 36f7345..62e9bea 100644
--- a/board/ti/beagle/beagle.c
+++ b/board/ti/beagle/beagle.c
@@ -166,8 +166,7 @@
 			timings->rfr_ctrl = SDP_3430_SDRC_RFR_CTRL_200MHz;
 			break;
 		}
-	case REVISION_XM_A:
-	case REVISION_XM_B:
+	case REVISION_XM_AB:
 	case REVISION_XM_C:
 		if (pop_mfr == 0) {
 			/* 256MB DDR */
@@ -240,8 +239,7 @@
 	case REVISION_C4:
 		omap3_dss_panel_config(&dvid_cfg);
 		break;
-	case REVISION_XM_A:
-	case REVISION_XM_B:
+	case REVISION_XM_AB:
 	case REVISION_XM_C:
 	default:
 		omap3_dss_panel_config(&dvid_cfg_xm);
@@ -260,12 +258,11 @@
 	case REVISION_AXBX:
 	case REVISION_CX:
 	case REVISION_C4:
-	case REVISION_XM_A:
 		gpio_request(170, "");
 		gpio_direction_output(170, 0);
 		gpio_set_value(170, 1);
 		break;
-	case REVISION_XM_B:
+	case REVISION_XM_AB:
 	case REVISION_XM_C:
 	default:
 		#define GPIODATADIR1 (TWL4030_BASEADD_GPIO+3)
@@ -343,19 +340,9 @@
 					TWL4030_PM_RECEIVER_VAUX2_DEV_GRP,
 					TWL4030_PM_RECEIVER_DEV_GRP_P1);
 		break;
-	case REVISION_XM_A:
-		printf("Beagle xM Rev A\n");
-		setenv("beaglerev", "xMA");
-		MUX_BEAGLE_XM();
-		/* Set VAUX2 to 1.8V for EHCI PHY */
-		twl4030_pmrecv_vsel_cfg(TWL4030_PM_RECEIVER_VAUX2_DEDICATED,
-					TWL4030_PM_RECEIVER_VAUX2_VSEL_18,
-					TWL4030_PM_RECEIVER_VAUX2_DEV_GRP,
-					TWL4030_PM_RECEIVER_DEV_GRP_P1);
-		break;
-	case REVISION_XM_B:
-		printf("Beagle xM Rev B\n");
-		setenv("beaglerev", "xMB");
+	case REVISION_XM_AB:
+		printf("Beagle xM Rev A/B\n");
+		setenv("beaglerev", "xMAB");
 		MUX_BEAGLE_XM();
 		/* Set VAUX2 to 1.8V for EHCI PHY */
 		twl4030_pmrecv_vsel_cfg(TWL4030_PM_RECEIVER_VAUX2_DEDICATED,
@@ -468,8 +455,7 @@
 
 	twl4030_power_init();
 	switch (get_board_revision()) {
-	case REVISION_XM_A:
-	case REVISION_XM_B:
+	case REVISION_XM_AB:
 		twl4030_led_init(TWL4030_LED_LEDEN_LEDBON);
 		break;
 	default:
diff --git a/board/ti/beagle/beagle.h b/board/ti/beagle/beagle.h
index 76be358..6dd2ffe 100644
--- a/board/ti/beagle/beagle.h
+++ b/board/ti/beagle/beagle.h
@@ -23,8 +23,7 @@
 #define REVISION_AXBX	0x7
 #define REVISION_CX	0x6
 #define REVISION_C4	0x5
-#define REVISION_XM_A	0x0
-#define REVISION_XM_B	0x1
+#define REVISION_XM_AB	0x0
 #define REVISION_XM_C	0x2
 
 /*