nb/intel/sandybridge: Remove unnecessary declaration

Change-Id: If99fd6511fcea474a1398d2b680e0df4bb1a229b
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39755
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/northbridge/intel/sandybridge/raminit_common.h

@@ -72,8 +72,6 @@ struct ram_rank_timings {
 	} lanes[NUM_LANES];
 };
 
-struct ramctr_timing_st;
-
 typedef struct ramctr_timing_st {
 	u16 spd_crc[NUM_CHANNELS][NUM_SLOTS];
 	int sandybridge;