regmap: Use flexible sleep

The multi-reg write function uses udelay(), which is a busy-loop based
delaying function that is not suitable for a long delays. Hence let's
replace the udelay() with fsleep(), which is flexible sleep function that
selects best delay function based on the delay-time.
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20200830185356.5365-3-digetx@gmail.comSigned-off-by: NMark Brown <broonie@kernel.org>

drivers/base/regmap/regmap.c

@@ -2231,7 +2231,7 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map,
 					return ret;
 
 				if (regs[i].delay_us)
-					udelay(regs[i].delay_us);
+					fsleep(regs[i].delay_us);
 
 				base += n;
 				n = 0;
@@ -2268,7 +2268,7 @@ static int _regmap_multi_reg_write(struct regmap *map,
 				return ret;
 
 			if (regs[i].delay_us)
-				udelay(regs[i].delay_us);
+				fsleep(regs[i].delay_us);
 		}
 		return 0;
 	}