regulator: max1586: Constify v6_voltages_uv table

Make v6_voltages_uv to be const unsigned int.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/max1586.c

@@ -56,7 +56,7 @@ struct max1586_data {
  *   set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
  * As regulator framework doesn't accept voltages to be 0V, we use 1uV.
  */
-static int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
+static const unsigned int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
 
 /*
  * V3 voltage