soc/intel/adl/chip.h: Rename max_dram_speed to include units

The unit of dram speed is MT/s so append it on variable name.

BUG=b:229549930
BRANCH=none
TEST=build coreboot without error

Signed-off-by: Scott Chao <scott_chao@wistron.corp-partner.google.com>
Change-Id: I83c780440613050c0202f95d5f64991b61d9c280
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63735
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>

src/soc/intel/alderlake/chip.h

@@ -484,7 +484,7 @@ struct soc_intel_alderlake_config {
 	*/
 	struct vr_config domain_vr_config[NUM_VR_DOMAINS];
 
-	uint16_t max_dram_speed;
+	uint16_t max_dram_speed_mts;
 
 	enum {
 		SLP_S3_ASSERTION_DEFAULT,