soc/amd/stoneyridge/pstate_util: fix off by one in P-state MSR number

There are 8 P-state MSRs and not only 7.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ic2899b6e454233c6cbb8fc1e439ff069c4d3d3a9
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76545
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>

src/soc/amd/stoneyridge/pstate_util.c

@@ -21,7 +21,7 @@ static bool all_pstates_have_same_frequency_id(void)
 	bool first = true;
 	uint32_t frequency_id;
 
-	for (i = 0; i < 7; i++) {
+	for (i = 0; i < 8; i++) {
 		pstate_reg.raw = rdmsr(PSTATE_MSR(i)).raw;
 
 		if (!pstate_reg.pstate_en)