clk: vc5: Use "idt,voltage-microvolt" instead of "idt,voltage-microvolts"

Commit 45c94018 ("dt-bindings: clk: versaclock5: convert to
yaml") accidentally changed "idt,voltage-microvolts" to
"idt,voltage-microvolt" in the DT bindings, while the driver still used
the former.

Update the driver to match the bindings, as
Documentation/devicetree/bindings/property-units.txt actually recommends
using "microvolt".

Fixes: 260249f9 ("clk: vc5: Enable addition output configurations of the Versaclock")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201218125253.3815567-1-geert+renesas@glider.beReviewed-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk-versaclock5.c

@@ -739,8 +739,8 @@ static int vc5_update_power(struct device_node *np_output,
 {
 	u32 value;
 
-	if (!of_property_read_u32(np_output,
-				  "idt,voltage-microvolts", &value)) {
+	if (!of_property_read_u32(np_output, "idt,voltage-microvolt",
+				  &value)) {
 		clk_out->clk_output_cfg0_mask |= VC5_CLK_OUTPUT_CFG0_PWR_MASK;
 		switch (value) {
 		case 1800000: