fpga: add configuration for the FPGA KUnit test suites.

Add configuration for the KUnit test suites for the core components
of the FPGA subsystem.

Signed-off-by: Marco Pagani <[e-mail]>
Acked-by: Xu Yilun <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Xu Yilun <[e-mail]>

drivers/fpga/Kconfig

···
 	  FPGA manager driver support for Lattice FPGAs programming over slave
 	  SPI sysCONFIG interface.
 
+source "drivers/fpga/tests/Kconfig"
+
 endif # FPGA

drivers/fpga/Makefile

···
 
 # Drivers for FPGAs which implement DFL
 obj-$(CONFIG_FPGA_DFL_PCI)		+= dfl-pci.o
+
+# KUnit tests
+obj-$(CONFIG_FPGA_KUNIT_TESTS)		+= tests/

drivers/fpga/tests/.kunitconfig

···
+CONFIG_KUNIT=y
+CONFIG_FPGA=y
+CONFIG_FPGA_REGION=y
+CONFIG_FPGA_BRIDGE=y
+CONFIG_FPGA_KUNIT_TESTS=y

drivers/fpga/tests/Kconfig

···
+config FPGA_KUNIT_TESTS
+	tristate "KUnit test for the FPGA subsystem" if !KUNIT_ALL_TESTS
+	depends on FPGA && FPGA_REGION && FPGA_BRIDGE && KUNIT=y
+	default KUNIT_ALL_TESTS
+        help
+          This builds unit tests for the FPGA subsystem
+
+          For more information on KUnit and unit tests in general,
+          please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+          If unsure, say N.

drivers/fpga/tests/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for KUnit test suites for the FPGA subsystem
+#
+
+obj-$(CONFIG_FPGA_KUNIT_TESTS) += fpga-mgr-test.o fpga-bridge-test.o fpga-region-test.o