soundwire: remove SDW_REG_SHIFT()

soundwire had defined SDW_REG_SHIFT to calculate shift values for
bitmasks, but now that we have better things in bitfield.h, remove this.
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Tested-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200903114504.1202143-10-vkoul@kernel.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

include/linux/soundwire/sdw_registers.h

@@ -4,13 +4,6 @@
 #ifndef __SDW_REGISTERS_H
 #define __SDW_REGISTERS_H
 
-/*
- * typically we define register and shifts but if one observes carefully,
- * the shift can be generated from MASKS using few bit primitaives like ffs
- * etc, so we use that and avoid defining shifts
- */
-#define SDW_REG_SHIFT(n)			(ffs(n) - 1)
-
 /*
  * SDW registers as defined by MIPI 1.2 Spec
  */