clk: imx8mn: fix imx8mn_enet_phy_sels clocks list

According to the "Clock Root" table of the reference manual (document
IMX8MNRM Rev 2, 07/2022):

     Clock Root         offset     Source Select (CCM_TARGET_ROOTn[MUX])
        ...              ...                    ...
 ENET_PHY_REF_CLK_ROOT  0xAA80            000 - 24M_REF_CLK
                                          001 - SYSTEM_PLL2_DIV20
                                          010 - SYSTEM_PLL2_DIV8
                                          011 - SYSTEM_PLL2_DIV5
                                          100 - SYSTEM_PLL2_DIV2
                                          101 - AUDIO_PLL1_CLK
                                          110 - VIDEO_PLL_CLK
                                          111 - AUDIO_PLL2_CLK
        ...              ...                    ...

while the imx8mn_enet_phy_sels list didn't contained audio_pll1_out for
source select bits 101b.

Fixes: 96d6392b

 ("clk: imx: Add support for i.MX8MN clock driver")
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Acked-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20221117113637.1978703-6-dario.binacchi@amarulasolutions.com