cpu/x86: Declare smi_release_lock() static

Change-Id: I535ff1b16b1fa7c3c8c14b2be7eac32568f16077
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34194
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/cpu/x86/smm/smihandler.c

@@ -47,7 +47,7 @@ static int smi_obtain_lock(void)
 	return (ret == SMI_UNLOCKED);
 }
 
-void smi_release_lock(void)
+static void smi_release_lock(void)
 {
 	asm volatile (
 		"movb %1, %%al\n"

src/include/cpu/x86/smm.h

@@ -501,10 +501,6 @@ void mainboard_smi_gpi(u32 gpi_sts);
 int  mainboard_smi_apmc(u8 data);
 void mainboard_smi_sleep(u8 slp_typ);
 
-#if !CONFIG(SMM_TSEG)
-void smi_release_lock(void);
-#endif
-
 /* This is the SMM handler. */
 extern unsigned char _binary_smm_start[];
 extern unsigned char _binary_smm_end[];