kconfig: Convert FPGA_SOCFPGA configuration to Kconfig

This converts the following to Kconfig:
   CONFIG_FPGA_SOCFPGA

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: Dinh Nguyen <dinguyen@kernel.org>
diff --git a/configs/socfpga_vining_fpga_defconfig b/configs/socfpga_vining_fpga_defconfig
index 8a49b8b..5f4c302 100644
--- a/configs/socfpga_vining_fpga_defconfig
+++ b/configs/socfpga_vining_fpga_defconfig
@@ -46,6 +46,7 @@
 CONFIG_DFU_MMC=y
 CONFIG_DFU_RAM=y
 CONFIG_DFU_SF=y
+CONFIG_FPGA_SOCFPGA=y
 CONFIG_DM_GPIO=y
 CONFIG_DWAPB_GPIO=y
 CONFIG_LED_STATUS=y