Convert CONFIG_TWL4030_LED et al to Kconfig

This converts the following to Kconfig:
   CONFIG_TWL4030_LED
   CONFIG_TWL4030_INPUT

This also removes dead references to:
   CONFIG_TWL4030_KEYPAD

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/configs/nokia_rx51_defconfig b/configs/nokia_rx51_defconfig
index b213a18..fe2ecf6 100644
--- a/configs/nokia_rx51_defconfig
+++ b/configs/nokia_rx51_defconfig
@@ -22,6 +22,7 @@
 CONFIG_CMD_EXT4=y
 CONFIG_CMD_FAT=y
 # CONFIG_NET is not set
+CONFIG_TWL4030_LED=y
 CONFIG_MMC_OMAP_HS=y
 CONFIG_CONS_INDEX=3
 CONFIG_SYS_NS16550=y