clk: imx7ulp: do not export out IMX7ULP_CLK_MIPI_PLL clock

The mipi pll clock comes from the MIPI PHY PLL output, so
it should not be a fixed clock.

MIPI PHY PLL is in the MIPI DSI space, and it is used as
the bit clock for transferring the pixel data out and its
output clock is configured according to the display mode.

So it should be used only for MIPI DSI and not be exported
out for other usages.

Signed-off-by: Fancy Fang <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

Documentation/devicetree/bindings/clock/imx7ulp-clock.txt

···
 		 <&scg1 IMX7ULP_CLK_APLL_PFD0>,
 		 <&scg1 IMX7ULP_CLK_UPLL>,
 		 <&scg1 IMX7ULP_CLK_SOSC_BUS_CLK>,
-		 <&scg1 IMX7ULP_CLK_MIPI_PLL>,
 		 <&scg1 IMX7ULP_CLK_FIRC_BUS_CLK>,
 		 <&scg1 IMX7ULP_CLK_ROSC>,
 		 <&scg1 IMX7ULP_CLK_SPLL_BUS_CLK>;

drivers/clk/imx/clk-imx7ulp.c

···
 static const char * const ddr_sels[]		= { "apll_pfd_sel", "dummy", "dummy", "dummy", };
 static const char * const nic_sels[]		= { "firc", "ddr_clk", };
 static const char * const periph_plat_sels[]	= { "dummy", "nic1_bus_clk", "nic1_clk", "ddr_clk", "apll_pfd2", "apll_pfd1", "apll_pfd0", "upll", };
-static const char * const periph_bus_sels[]	= { "dummy", "sosc_bus_clk", "mpll", "firc_bus_clk", "rosc", "nic1_bus_clk", "nic1_clk", "spll_bus_clk", };
+static const char * const periph_bus_sels[]	= { "dummy", "sosc_bus_clk", "dummy", "firc_bus_clk", "rosc", "nic1_bus_clk", "nic1_clk", "spll_bus_clk", };
 static const char * const arm_sels[]		= { "divcore", "dummy", "dummy", "hsrun_divcore", };
 
 /* used by sosc/sirc/firc/ddr/spll/apll dividers */
···
 	clks[IMX7ULP_CLK_SOSC]		= imx_obtain_fixed_clk_hw(np, "sosc");
 	clks[IMX7ULP_CLK_SIRC]		= imx_obtain_fixed_clk_hw(np, "sirc");
 	clks[IMX7ULP_CLK_FIRC]		= imx_obtain_fixed_clk_hw(np, "firc");
-	clks[IMX7ULP_CLK_MIPI_PLL]	= imx_obtain_fixed_clk_hw(np, "mpll");
 	clks[IMX7ULP_CLK_UPLL]		= imx_obtain_fixed_clk_hw(np, "upll");
 
 	/* SCG1 */

include/dt-bindings/clock/imx7ulp-clock.h

···
 #define IMX7ULP_CLK_NIC1_DIV		36
 #define IMX7ULP_CLK_NIC1_BUS_DIV	37
 #define IMX7ULP_CLK_NIC1_EXT_DIV	38
+/* IMX7ULP_CLK_MIPI_PLL is unsupported and shouldn't be used in DT */
 #define IMX7ULP_CLK_MIPI_PLL		39
 #define IMX7ULP_CLK_SIRC		40
 #define IMX7ULP_CLK_SOSC_BUS_CLK	41