mb/google/volteer: Fix a few devicetree device refs

Commit b0e169ac85 included a few small omissions and typos when
converting 'device pci xx.y' to 'device ref blah' after adding the new
chipset.cb file for TGL. This patch fixes these errors:
1) MIPI camera support requires I2C2 & I2C3 enabled
2) Malefor SAR sensor is on I2C2, not I2C3

BUG=b:175165653
TEST=abuild -p none -t google/volteer -x -a -c max

Change-Id: I577957d67f47bbe88bbc2535fb1cb5c8f7390438
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48511
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>
Reviewed-by: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>

src/mainboard/google/volteer/variants/baseboard/devicetree.cb

@@ -464,6 +464,9 @@ chip soc/intel/tigerlake
 				device generic 0 on end
 			end
 		end
+		# MIPI camera devices are on I2C buses 2 and 3
+		device ref i2c2 on end
+		device ref i2c3 on end
 		device ref heci1 on end
 		device ref sata on end
 		device ref pcie_rp1 on end

src/mainboard/google/volteer/variants/malefor/overridetree.cb

@@ -63,7 +63,7 @@ chip soc/intel/tigerlake
 				device i2c 5d on end
 			end
 		end
-		device ref i2c3 on
+		device ref i2c2 on
 			chip drivers/i2c/sx9310
 				register "desc" = ""SAR0 Proximity Sensor""
 				register "irq" = "ACPI_IRQ_LEVEL_LOW(GPP_F14_IRQ)"