Convert CONFIG_CMDLINE_PS_SUPPORT to Kconfig

This converts the following to Kconfig:
   CONFIG_CMDLINE_PS_SUPPORT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/socfpga_vining_fpga_defconfig b/configs/socfpga_vining_fpga_defconfig
index 52084b8..331975a 100644
--- a/configs/socfpga_vining_fpga_defconfig
+++ b/configs/socfpga_vining_fpga_defconfig
@@ -27,6 +27,7 @@
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_SPI_LOAD=y
 CONFIG_SYS_SPI_U_BOOT_OFFS=0x40000
+CONFIG_CMDLINE_PS_SUPPORT=y
 CONFIG_CMD_ASKENV=y
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_EEPROM=y