platform/x86: intel_pmc_core: Mark local function static

0day reports:

drivers/platform/x86/intel_pmc_core.c:833:5: sparse:
	symbol 'quirk_xtal_ignore' was not declared. Should it be static?

Mark the function static since it is indeed only called locally.

Cc: Rajneesh Bhardwaj <rajneesh.bhardwaj@linux.intel.com>
Fixes: 238f9c11 ("platform/x86: intel_pmc_core: Quirk to ignore XTAL shutdown")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/intel_pmc_core.c

@@ -828,7 +828,7 @@ static const struct pci_device_id pmc_pci_ids[] = {
  * the platform BIOS enforces 24Mhx Crystal to shutdown
  * before PMC can assert SLP_S0#.
  */
-int quirk_xtal_ignore(const struct dmi_system_id *id)
+static int quirk_xtal_ignore(const struct dmi_system_id *id)
 {
 	struct pmc_dev *pmcdev = &pmc;
 	u32 value;