soc/intel/xeon_sp/skx: Remove invalid declaration

The declaration is autogenerated inside static.c file
from the pathname. The declaration here also lacked _skx_
part from the name.

Change-Id: I3adce9147e9376f6d73e410fdd4c0ee800178b58
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41710
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/intel/xeon_sp/skx/chip.h

@@ -71,8 +71,6 @@ struct soc_intel_xeon_sp_skx_config {
 	uint32_t gen4_dec;
 };
 
-extern struct chip_operations soc_intel_xeon_sp_ops;
-
 typedef struct soc_intel_xeon_sp_skx_config config_t;
 
 #endif