soc/intel/common/block/acpi: Fix error in shift operation for GPCL

CB:41454 updated northbridge.asl to ASL2.0 syntax. During this, GPCL
was incorrectly updated to use << (ShiftLeft) instead of >>
(ShiftRight). This change fixes the error in GPCL by updating it to
use >> (ShiftRight).

TEST=Verified using --timeless option to abuild that the resulting
coreboot.rom is same as without the ASL2.0 syntax changes for hatch.

Change-Id: I36469cb3b0bcc595acf0e43808d6a574986cad68
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41519
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/common/block/acpi/acpi/northbridge.asl

@@ -229,7 +229,7 @@ Method (GPCB, 0, Serialized)
 /* Get PCIe Length */
 Method (GPCL, 0, Serialized)
 {
-	Local0 = 0x10000000 << \_SB.PCI0.MCHC.PXSZ
+	Local0 = 0x10000000 >> \_SB.PCI0.MCHC.PXSZ
 	Return (Local0)
 }