intel: Get rid of smm_get_pmbase

Change-Id: I2b3168c600a81502f9cd1ff3203c492cf026e532
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/27279
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/include/cpu/x86/smm.h

@@ -507,9 +507,6 @@ void smi_release_lock(void);
 extern unsigned char _binary_smm_start[];
 extern unsigned char _binary_smm_end[];
 
-/* Get PMBASE address */
-u16 smm_get_pmbase(void);
-
 struct smm_runtime {
 	u32 smbase;
 	u32 save_state_size;