src/target/mips_m4k.c: set missing flag in set_watchpoint

Without the fix, will see "Can not find free FP Comparator" error log

Change-Id: Id0d91cc02b7055e44d27507f9c05ccd48ff49838
Signed-off-by: Nima Palizban <[email protected]>
Fixes: fb43f1f (target: Rework 'set' variable of break-/watchpoints)
Reviewed-on: https://review.openocd.org/c/openocd/+/7389
Tested-by: jenkins
Reviewed-by: Tomas Vanek <[email protected]>
Reviewed-by: Antonio Borneo <[email protected]>

Author: npalizban

src/target/mips_m4k.c

@@ -900,7 +900,7 @@ static int mips_m4k_set_watchpoint(struct target *target,
 			LOG_ERROR("BUG: watchpoint->rw neither read, write nor access");
 	}
 
-	watchpoint->number = wp_num;
+	watchpoint_set(watchpoint, wp_num);
 	comparator_list[wp_num].used = 1;
 	comparator_list[wp_num].bp_value = watchpoint->address;