clk: imx8mp: Add audio shared gate

According to the RM, the CCGR101 is shared for the following root clocks:
- AUDIO_AHB_CLK_ROOT
- AUDIO_AXI_CLK_ROOT
- SAI1_CLK_ROOT
- SAI2_CLK_ROOT
- SAI3_CLK_ROOT
- SAI5_CLK_ROOT
- SAI6_CLK_ROOT
- SAI7_CLK_ROOT
- PDM_CLK_ROOT

IMX8MP_CLK_AUDIO_ROOT is same as AUDIO_AHB_CLK_ROOT
which can avoid break any users.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/1667811007-19222-3-git-send-email-shengjiu.wang@nxp.com