MX6UL: Add definition for UART6 base address

Define the UART6_BASE_ADDR for MX6UL.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>

arch/arm/include/asm/arch-mx6/imx-regs.h

@@ -274,6 +274,7 @@
 #define IP2APB_TZASC1_BASE_ADDR     (AIPS2_OFF_BASE_ADDR + 0x50000)
 #ifdef CONFIG_MX6UL
 #define QSPI0_BASE_ADDR             (AIPS2_OFF_BASE_ADDR + 0x60000)
+#define UART6_BASE_ADDR             (AIPS2_OFF_BASE_ADDR + 0x7C000)
 #elif defined(CONFIG_MX6SX)
 #define SAI1_BASE_ADDR              (AIPS2_OFF_BASE_ADDR + 0x54000)
 #define AUDMUX_BASE_ADDR            (AIPS2_OFF_BASE_ADDR + 0x58000)