mb/google/brya/var/brask: Enable ASPM of RTL8125

Brask cannot pass powerd_dbus_suspend test because the NIC does not
enter ASPM L1.2. Here we add "enable_aspm_l1_2" in devicetree for
RTL8125 to enable ASPM L1.2.

BUG=b:204309459
BRANCH=None
TEST=emerge and test with command powerd_dbus_suspend

Signed-off-by: Alan Huang <alan-huang@quanta.corp-partner.google.com>
Change-Id: I9a56df1d68696f409f9ee681d37de6759a588d80
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61268
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/mainboard/google/brya/variants/brask/overridetree.cb

@@ -92,6 +92,7 @@ chip soc/intel/alderlake
 				register "led_feature" = "0xe0"
 				register "customized_led0" = "0x23f"
 				register "customized_led2" = "0x028"
+				register "enable_aspm_l1_2" = "1"
 				device pci 00.0 on end
 			end
 		end # RTL8125 Ethernet NIC