drivers: Enable FPGA driver build on SPL

Enable FPGA driver build for Arria 10 SPL because FPGA driver is
needed by Arria 10 SPL to configure and getting DDR up before
loading U-boot into DDR and booting from there.
Signed-off-by: NTien Fong Chee <tien.fong.chee@intel.com>
Reviewed-by: NLey Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: NDinh Nguyen <dinguyen@kernel.org>

drivers/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_OMAP_USB_PHY) += usb/phy/
 obj-$(CONFIG_SPL_SATA_SUPPORT) += ata/ scsi/
 obj-$(CONFIG_SPL_USB_HOST_SUPPORT) += block/
 obj-$(CONFIG_SPL_MMC_SUPPORT) += block/
+obj-$(CONFIG_SPL_FPGA_SUPPORT) += fpga/
 endif
 
 ifdef CONFIG_TPL_BUILD