mb/google/brya/acpi: Add L23 entry/exit sequences during dGPU GCOFF

When the dGPU is entering GCOFF, the link should first be placed into
L2/L3 as appropriate for the design, then when exiting, the link should
be placed back into L0. This patch fixes that oversight.

BUG=b:239719056
TEST=build

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: Ia3bdfe5641216675e06ebe82ffe58bf8c049b26b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66200
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Ivy Jian <ivy.jian@quanta.corp-partner.google.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>

src/mainboard/google/brya/acpi/power.asl

@@ -221,6 +221,7 @@ Method (NPON, 0, Serialized)
 	Else
 	{
 		PGON ()
+		\_SB.PCI0.PEG0.LD23 ()
 	}
 }
 
@@ -239,6 +240,7 @@ Method (NPOF, 0, Serialized)
 	}
 	Else
 	{
+		\_SB.PCI0.PEG0.DL23 ()
 		PGOF ()
 	}
 }