clk: meson: axg: add the fractional part of the fixed_pll

The fixed_pll also has a fractional part. On axg s400 board, without
this parameter, the calculated rate is off by ~8Mhz (0,4%). The fixed_pll
being the root of the peripheral clock tree, this error is propagated to
the rest of the clocks

Adding the definition of the parameter fixes the problem

Fixes: 78b4af312f ("clk: meson-axg: add clock controller drivers")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>

drivers/clk/meson/axg.c

@@ -37,6 +37,11 @@ static struct meson_clk_pll axg_fixed_pll = {
 		.shift   = 16,
 		.width   = 2,
 	},
+	.frac = {
+		.reg_off = HHI_MPLL_CNTL2,
+		.shift   = 0,
+		.width   = 12,
+	},
 	.lock = &meson_clk_lock,
 	.hw.init = &(struct clk_init_data){
 		.name = "fixed_pll",