soc/intel/{adl, mtl, ptl}: Drop CLFLUSH (X86_CLFLUSH_CAR) config

This patch drops the X86_CLFLUSH_CAR config from the latest Intel SoCs
(ADL, MTL, PTL) following the switch to WC (Write-Combining) MTRR type
for the RAMTOP range.

Previously, with WB (Write-Back) caching for RAMTOP, CLFLUSH was
crucial to ensure data consistency, as WB caches both reads and writes.
However, since the RAMTOP range now relies on WC MTRR, the role of
CLFLUSH becomes less critical.

Removing CLFLUSH in this scenario can improve performance, as it avoids
unnecessary cache invalidations.

BUG=b:373290479
TEST=Able to build and boot google/trulo.

Change-Id: I3631a58ba03cd2fbe8821bc89b1ca7226c2f0fd4
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/85028
Reviewed-by: Dinesh Gehlot <digehlot@google.com>
Reviewed-by: V Sowmya <v.sowmya@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jayvik Desai <jayvik@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

0 files changed, 0 insertions, 0 deletions