regulator: hi6421v600: Fix .vsel_mask setting

Take ldo3_voltages as example, the ARRAY_SIZE(ldo3_voltages) is 16.
i.e. the valid selector is 0 ~ 0xF.
But in current code the vsel_mask is "(1 << 15) - 1", i.e. 0x7FFF. Fix it.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20210529013236.373847-1-axel.lin@ingics.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/staging/hikey9xx/hi6421v600-regulator.c

@@ -83,7 +83,7 @@ static const unsigned int ldo34_voltages[] = {
 			.owner		= THIS_MODULE,			       \
 			.volt_table	= vtable,			       \
 			.n_voltages	= ARRAY_SIZE(vtable),		       \
-			.vsel_mask	= (1 << (ARRAY_SIZE(vtable) - 1)) - 1, \
+			.vsel_mask	= ARRAY_SIZE(vtable) - 1,	       \
 			.vsel_reg	= vreg,				       \
 			.enable_reg	= ereg,				       \
 			.enable_mask	= emask,			       \