kconfig: Improve 'General setup' menu docs.

 - Add documentation for COMPILER_GCC, and COMPILER_LLVM_CLANG.

 - SCANBUILD_ENABLE, CCACHE: Amend documentation.

 - SCANBUILD_REPORT_LOCATION: Document default dir, names of scan-build dirs.

 - INCLUDE_CONFIG_FILE: Add more verbose docs, show how to use it.

 - Fix typos/cosmetics/indentation, improve wording on some items.

Change-Id: I6b67b2c777868e4421405caaffe6631e69dddad2
Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Reviewed-on: http://review.coreboot.org/893
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
1 file changed