omap3evm: ehci: Update EHCI support on OMAP3EVM (Rev >= E)

Added runtime programming for the differences in EHCI interface between
OMAP3EVM revisions (Rev >= E) and (Rev < E).

Changes:
	- EHCI PHY reset GPIO pin is 21 on Rev >= E while Rev < E
	  uses GPIO pin 135.
	- Rev >= E uses EHCI Vbus enable GPIO22 line.
	- Rev >= E uses GPIO61 to select EHCI port either on main board or
	  on Mistral Daughter Card (MDC). OMAP3EVM Rev < E doesn't have
	  EHCI port on main board.
	- Currently GPIO61 it programmed to enable EHCI port on main
	  board only.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>

arch/arm/plat-omap/include/plat/mux.h

@@ -849,6 +849,11 @@ enum omap34xx_index {
 
 	/* SYS_NIRQ T2 INT1 */
 	AF26_34XX_SYS_NIRQ,
+
+	/* EHCI GPIO's for OMAP3EVM (Rev >= E) */
+	AH14_34XX_GPIO21,
+	AF9_34XX_GPIO22,
+	U3_34XX_GPIO61,
 };
 
 struct omap_mux_cfg {