perf/arm-cmn: Improve format attr printing

Take full advantage of our formats being stored in bitfield form, and
make the printing even more robust and simple by letting printk do all
the hard work of formatting bitlists.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Link: https://lore.kernel.org/r/50459f2d48fc62310a566863dbf8a7c14361d363.1725474584.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: rmurphy-arm

drivers/perf/arm-cmn.c

@@ -1280,15 +1280,11 @@ static ssize_t arm_cmn_format_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
 	struct arm_cmn_format_attr *fmt = container_of(attr, typeof(*fmt), attr);
-	int lo = __ffs(fmt->field), hi = __fls(fmt->field);
-
-	if (lo == hi)
-		return sysfs_emit(buf, "config:%d\n", lo);
 
 	if (!fmt->config)
-		return sysfs_emit(buf, "config:%d-%d\n", lo, hi);
+		return sysfs_emit(buf, "config:%*pbl\n", 64, &fmt->field);
 
-	return sysfs_emit(buf, "config%d:%d-%d\n", fmt->config, lo, hi);
+	return sysfs_emit(buf, "config%d:%*pbl\n", fmt->config, 64, &fmt->field);
 }
 
 #define _CMN_FORMAT_ATTR(_name, _cfg, _fld)				\