platform/x86: amd-pmc: Make amd_pmc_stb_debugfs_fops static

amd_pmc_stb_debugfs_fops is not used outside of amd-pmc.c, make it
static.

Cc: Sanket Goswami <Sanket.Goswami@amd.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220117112644.260168-1-hdegoede@redhat.com

drivers/platform/x86/amd-pmc.c

@@ -226,7 +226,7 @@ static int amd_pmc_stb_debugfs_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
-const struct file_operations amd_pmc_stb_debugfs_fops = {
+static const struct file_operations amd_pmc_stb_debugfs_fops = {
 	.owner = THIS_MODULE,
 	.open = amd_pmc_stb_debugfs_open,
 	.read = amd_pmc_stb_debugfs_read,