mb/google/rex: Skip sending the MBP HOB to save boot time

This change is to skip sending the MBP HOB since coreboot doesn't
use it and also helps to reduce the boot time by ~40 ms.

Boot time data
Before:
* 955:returning from FspSiliconInit 1,656,985 (274,416)
After:
* 955:returning from FspSiliconInit 1,593,036 (233,286)

BUG=b:252410202
TEST=Verified that boot time is reduced by ~40 msec.

Signed-off-by: Wonkyu Kim <wonkyu.kim@intel.com>
Change-Id: I0d4f66940529b8d38d9658c769feba8b5c9b715e
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68418
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

src/mainboard/google/rex/variants/rex0/overridetree.cb

@@ -69,6 +69,8 @@ chip soc/intel/meteorlake
 		[PchSerialIoIndexI2C5] = PchSerialIoPci,
 	}"
 
+	register "skip_mbp_hob" = "1"
+
 	# Intel Common SoC Config
 	#+-------------------+---------------------------+
 	#| Field             |  Value                    |