media: imx274: document reset delays more clearly

Document the unit to avoid having to look through the code to compute it.
Also clarify that these are min and max values.
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/i2c/imx274.c

@@ -87,7 +87,7 @@
 #define IMX274_SHR_LIMIT_CONST			(4)
 
 /*
- * Constants for sensor reset delay
+ * Min and max sensor reset delay (microseconds)
  */
 #define IMX274_RESET_DELAY1			(2000)
 #define IMX274_RESET_DELAY2			(2200)