tmv4c123g-launchpad: Add Tiva ADC support to the TM4C123G-Launchpad. From Calvin Maguranis.

configs/tm4c123g-launchpad/src/Makefile

 ############################################################################
 # configs/tm4c123g-launchpad/src/Makefile
 #
-#   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2014-2015 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -53,6 +53,10 @@ ifeq ($(CONFIG_TIVA_TIMER),y)
 CSRCS += tm4c_timer.c
 endif
 
+ifeq ($(CONFIG_TIVA_ADC),y)
+CHIP_CSRCS += tm4c_adc.c
+endif
+
 ifeq ($(CONFIG_MTD_AT24XX),y)
 ifeq ($(CONFIG_TIVA_I2C0),y)
 CSRCS += tm4c_at24.c