starlabs: Convert EC_GPE_SCI to Kconfig

Convert EC_GPI_SCI to Kconfig option with default value of
0x50 that is used by most boards.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I8d47ebe76394fe1bcb217e0c6211db1566f82189
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60229
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/ec/starlabs/merlin/Kconfig

@@ -55,3 +55,7 @@ config EC_STARLABS_MERLIN
 config EC_VARIANT_DIR
 	string
 	default "merlin" if EC_STARLABS_MERLIN
+
+config EC_GPE_SCI
+	hex
+	default 0x50

src/ec/starlabs/merlin/acpi/ec.asl

@@ -10,7 +10,7 @@ Scope (\_SB.PCI0.LPCB)
 	{
 		Name (_HID, EisaId ("PNP0C09"))
 		Name (_UID, 0x01)
-		Name (_GPE, EC_GPE_SCI)
+		Name (_GPE, CONFIG_EC_GPE_SCI)
 		Name (ECAV, 0x00)
 		Name (ECTK, 0x01)
 		Name (B2ST, 0x00)