soc/intel/common/block/smbus: Remove unused macro

TEST=Able to build and boot ADLRVP.

Change-Id: Ic92271700185977f0be83cbc1d3adde37d5b6253
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50747
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/soc/intel/common/block/smbus/smbuslib.h

@@ -18,6 +18,4 @@
 #define SMBXMITADD	0x4
 #define SMBHSTDAT0	0x5
 
-#define SMBUS_TIMEOUT	15	/* 15ms */
-
 #endif	/* SOC_INTEL_COMMON_BLOCK_SMBUS__LIB_H */