coresight: etm4x: Cleanup TRCBBCTLR register accesses

This is a no-op change for style and consistency and has no effect on
the binary output by the compiler. In sysreg.h fields are defined as
the register name followed by the field name and then _MASK. This
allows for grepping for fields by name rather than using magic numbers.
Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Link: https://lore.kernel.org/r/20220304171913.2292458-15-james.clark@arm.comSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/hwtracing/coresight/coresight-etm4x-sysfs.c

@@ -707,10 +707,10 @@ static ssize_t bb_ctrl_store(struct device *dev,
 	 * individual range comparators. If include then at least 1
 	 * range must be selected.
 	 */
-	if ((val & BIT(8)) && (BMVAL(val, 0, 7) == 0))
+	if ((val & TRCBBCTLR_MODE) && (FIELD_GET(TRCBBCTLR_RANGE_MASK, val) == 0))
 		return -EINVAL;
 
-	config->bb_ctrl = val & GENMASK(8, 0);
+	config->bb_ctrl = val & (TRCBBCTLR_MODE | TRCBBCTLR_RANGE_MASK);
 	return size;
 }
 static DEVICE_ATTR_RW(bb_ctrl);

drivers/hwtracing/coresight/coresight-etm4x.h

@@ -220,6 +220,9 @@
 
 #define TRCSSPCICRn_PC_MASK			GENMASK(7, 0)
 
+#define TRCBBCTLR_MODE				BIT(8)
+#define TRCBBCTLR_RANGE_MASK			GENMASK(7, 0)
+
 /*
  * System instructions to access ETM registers.
  * See ETMv4.4 spec ARM IHI0064F section 4.3.6 System instructions