clk: imx: imx8ulp: keep MU0_B clock enabled always

Keep the A35<->M33 MU0_B clock enabled always for low power
communication.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20230331063814.2462059-4-peng.fan@oss.nxp.com
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>

drivers/clk/imx/clk-imx8ulp.c

@@ -376,7 +376,7 @@ static int imx8ulp_clk_pcc3_init(struct platform_device *pdev)
 	clks[IMX8ULP_CLK_DMA1_CH29] = imx_clk_hw_gate("pcc_dma1_ch29", "xbar_ad_divplat", base + 0x7c, 30);
 	clks[IMX8ULP_CLK_DMA1_CH30] = imx_clk_hw_gate("pcc_dma1_ch30", "xbar_ad_divplat", base + 0x80, 30);
 	clks[IMX8ULP_CLK_DMA1_CH31] = imx_clk_hw_gate("pcc_dma1_ch31", "xbar_ad_divplat", base + 0x84, 30);
-	clks[IMX8ULP_CLK_MU0_B] = imx_clk_hw_gate("mu0_b", "xbar_ad_divplat", base + 0x88, 30);
+	clks[IMX8ULP_CLK_MU0_B] = imx_clk_hw_gate_flags("mu0_b", "xbar_ad_divplat", base + 0x88, 30, CLK_IS_CRITICAL);
 	clks[IMX8ULP_CLK_MU3_A] = imx_clk_hw_gate("mu3_a", "xbar_ad_divplat", base + 0x8c, 30);
 
 	imx_check_clk_hws(clks, clk_data->num);