ARM: socfpga_defconfig: Update defconfig for SoCFPGA

Clean up the socfpga_defconfig file by doing:
	make socfpga_defconfig
	make
	make savedefconfig

Then add the following to socfpga_defconfig:

CONFIG_SIGNALFD=y
CONFIG_REGULATOR=y
CONFIG_REGULATOR_FIXED_VOLTAGE=y
CONFIG_SRAM=y
CONFIG_DEVTMPFS_MOUNT=y
CONFIG_CONFIGFS_FS=y
CONFIG_PMBUS=y
CONFIG_SENSORS_PMBUS=y
CONFIG_SENSORS_LTC2978=y
CONFIG_SENSORS_LTC2978_REGULATOR=y
CONFIG_PRINTK_TIME=y
CONFIG_EXT4_FS=y

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>