Revert "mb/google/zork/dalboz: Increase eMMC initial clock frequency"

This reverts commit c4a5acdabc.

Reason for revert: Dalboz is missing pull-up on cmd line, so 400khz is not possible.

TEST=Boot Dalboz
BUG=b:159823235, b:169940175
BRANCH=zork

Change-Id: I89653bfeefa522c17ee2d736215bc22aa445871c
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45004
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/mainboard/google/zork/variants/dalboz/overridetree.cb

@@ -37,12 +37,6 @@ chip soc/amd/picasso
 		.early_init = true,
 	}"
 
-	register "emmc_config" = "{
-		.timing = SD_EMMC_EMMC_HS400,
-		.sdr104_hs400_driver_strength = SD_EMMC_DRIVE_STRENGTH_A,
-		.init_khz_preset = 400,
-	}"
-
 	# See AMD 55570-B1 Table 13: PCI Device ID Assignments.
 	device domain 0 on
 		subsystemid 0x1022 0x1510 inherit