ARM: socfpga: Enable part command for socfpga platform

Enable CONFIG_CMD_PART item, as default environment requires it
and complains this command in unknown.

Signed-off-by: Andrey Zhizhikin <andrey.z@gmail.com>
diff --git a/configs/socfpga_vining_fpga_defconfig b/configs/socfpga_vining_fpga_defconfig
index c5dbe89..d34d302 100644
--- a/configs/socfpga_vining_fpga_defconfig
+++ b/configs/socfpga_vining_fpga_defconfig
@@ -39,6 +39,7 @@
 CONFIG_CMD_EXT4_WRITE=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
+CONFIG_CMD_PART=y
 CONFIG_MTDIDS_DEFAULT="nor0=ff705000.spi.0"
 CONFIG_MTDPARTS_DEFAULT="mtdparts=ff705000.spi.0:1m(u-boot),64k(env1),64k(env2),256k(samtec1),256k(samtec2),-(rcvrfs);"
 CONFIG_CMD_UBI=y