dim: make dim_calc_stats() inputs const pointers

Make the start and end arguments to dim_calc_stats() const pointers
to clarify that the function does not modify their values.

Signed-off-by: Caleb Sander Mateos <[e-mail]>
Reviewed-by: Vladimir Oltean <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Reviewed-by: Arthur Kiyanovski <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

include/linux/dim.h

···
  * Takes into consideration counter wrap-around.
  * Returned boolean indicates whether curr_stats are reliable.
  */
-bool dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
+bool dim_calc_stats(const struct dim_sample *start,
+		    const struct dim_sample *end,
 		    struct dim_stats *curr_stats);
 
 /**

lib/dim/dim.c

···
 }
 EXPORT_SYMBOL(dim_park_tired);
 
-bool dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
+bool dim_calc_stats(const struct dim_sample *start,
+		    const struct dim_sample *end,
 		    struct dim_stats *curr_stats)
 {
 	/* u32 holds up to 71 minutes, should be enough */