clk: meson: Fix GXL HDMI PLL fractional bits width

The GXL Documentation specifies 12 bits for the Fractional bit field,
bit the last bits have a different purpose that we cannot handle right
now, so update the bitwidth to have correct fractional calculations.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[narmstrong: added comment on GXL HHI_HDMI_PLL_CNTL register shift]
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lkml.kernel.org/r/20181121111922.1277-1-narmstrong@baylibre.com

drivers/clk/meson/gxbb.c

@@ -216,10 +216,16 @@ static struct clk_regmap gxl_hdmi_pll_dco = {
 			.shift   = 9,
 			.width   = 5,
 		},
+		/*
+		 * On gxl, there is a register shift due to
+		 * HHI_HDMI_PLL_CNTL1 which does not exist on gxbb,
+		 * so we use the HHI_HDMI_PLL_CNTL2 define from GXBB
+		 * instead which is defined at the same offset.
+		 */
 		.frac = {
 			.reg_off = HHI_HDMI_PLL_CNTL2,
 			.shift   = 0,
-			.width   = 12,
+			.width   = 10,
 		},
 		.l = {
 			.reg_off = HHI_HDMI_PLL_CNTL,