platform/x86/amd/pmc: Use FCH_PM_BASE definition

JIRA: https://issues.redhat.com/browse/RHEL-89441

commit 7094702
Author: Mario Limonciello <mario.limonciello@amd.com>
Date:   Tue Apr 22 18:48:29 2025 -0500

    platform/x86/amd/pmc: Use FCH_PM_BASE definition

    The s2idle MMIO quirk uses a scratch register in the FCH.
    Adjust the code to clarify that.

    Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Hans de Goede <hdegoede@redhat.com>
    Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
    Cc: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
    Cc: Yazen Ghannam <yazen.ghannam@amd.com>
    Cc: platform-driver-x86@vger.kernel.org
    Link: https://lore.kernel.org/r/20250422234830.2840784-5-superm1@kernel.org

Signed-off-by: David Arcari <darcari@redhat.com>

Author: darcari

arch/x86/include/asm/amd/fch.h

@@ -7,5 +7,6 @@
 /* Register offsets from PM base: */
 #define FCH_PM_DECODEEN			0x00
 #define FCH_PM_DECODEEN_SMBUS0SEL	GENMASK(20, 19)
+#define FCH_PM_SCRATCH			0x80
 
 #endif /* _ASM_X86_AMD_FCH_H_ */

drivers/platform/x86/amd/pmc/pmc-quirks.c

@@ -11,6 +11,7 @@
 #include <linux/dmi.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
+#include <asm/amd/fch.h>
 
 #include "pmc.h"
 
@@ -20,7 +21,7 @@ struct quirk_entry {
 };
 
 static struct quirk_entry quirk_s2idle_bug = {
-	.s2idle_bug_mmio = 0xfed80380,
+	.s2idle_bug_mmio = FCH_PM_BASE + FCH_PM_SCRATCH,
 };
 
 static struct quirk_entry quirk_spurious_8042 = {