ACPI: CPPC: Fix missing PCC check for guaranteed_perf

The current implementation overlooks the 'guaranteed_perf'
register in this check.

If the Guaranteed Performance register is located in the PCC
subspace, the function currently attempts to read it without
acquiring the lock and without sending the CMD_READ doorbell
to the firmware. This can result in reading stale data.

Fixes: 29523f095397 ("ACPI / CPPC: Add support for guaranteed performance")
Signed-off-by: Pengjie Zhang <[e-mail]>
Cc: 4.20+ <[e-mail]> # 4.20+
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/cppc_acpi.c

···
 	/* Are any of the regs PCC ?*/
 	if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
 		CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
-		CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
+		CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg) ||
+		CPC_IN_PCC(guaranteed_reg)) {
 		if (pcc_ss_id < 0) {
 			pr_debug("Invalid pcc_ss_id\n");
 			return -ENODEV;