soc/amd/stoneyridge: Use generic gpio library

Use the genric GPIO library. Add the required functions.
Also, update the Kahlee mainboard dependency to match.

Change-Id: I2ea562b052401efff3101f736788ca77d21e6de6
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/20543
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/stoneyridge/Kconfig

@@ -31,6 +31,7 @@ config CPU_SPECIFIC_OPTIONS
 	select ARCH_VERSTAGE_X86_32
 	select ARCH_ROMSTAGE_X86_32
 	select ARCH_RAMSTAGE_X86_32
+	select GENERIC_GPIO_LIB
 	select IOAPIC
 	select HAVE_USBDEBUG_OPTIONS
 	select HAVE_HARD_RESET