fsp2_0: Gather Kconfig declarations

Move more Kconfig declarations to drivers/intel/fsp2_0/ and document
them properly. This way, we don't have to repeat dependencies and have
the prompts in a common place. We can also easily hide the prompt for
the header path in case the FSP repository is used.

SP platforms were skipped as their Kconfig is too weird but they
shouldn't hold other platforms back.

Change-Id: Iba5af49bcd15427e9eb9b111e6c4cc9bcb7adcae
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40125
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>

src/drivers/intel/fsp2_0/Kconfig

@@ -31,13 +31,36 @@ config PLATFORM_USES_FSP2_1
 
 if PLATFORM_USES_FSP2_0
 
+config HAVE_INTEL_FSP_REPO
+	bool
+	help
+	  Select this, if the FSP binaries for the platform are public
+	  and available in 3rdparty/fsp/. When selecting this option, the
+	  platform must also set FSP_HEADER_PATH and FSP_FD_PATH correctly.
+
 config FSP_USE_REPO
 	bool "Use binaries of the Intel FSP repository on GitHub"
 	depends on HAVE_INTEL_FSP_REPO
 	default y
 	help
-	  When selecting this option, the SoC must set FSP_HEADER_PATH
-	  and FSP_FD_PATH correctly so FSP splitting works.
+	  Select this option to use the default FSP headers and binaries
+	  found in the IntelFsp GitHub repository at
+
+	    https://github.com/IntelFsp/FSP/
+
+	  If unsure, say Y.
+
+config FSP_HEADER_PATH
+	string "Location of FSP headers" if !FSP_USE_REPO
+	help
+	  Include directory with the FSP ABI header files.
+
+config FSP_FD_PATH
+	string
+	depends on FSP_USE_REPO
+	help
+	  Path to the FSP FD file that contains the individual FSP-T, FSP-M
+	  and FSP-S binaries.
 
 config ADD_FSP_BINARIES
 	bool "Add Intel FSP 2.0 binaries to CBFS" if !FSP_USE_REPO