dts: rk3588 pocket/next: fix i2s mclk frequency

• audio pitch is lower than normal on devices with rk3588+tlv320aic3100
• i2s mclk frequency wasn't configured
• turns out the rk3588 i2s mclk, when set to 12280000 Hz actually yields 12279999 Hz and the tlv320aic31xx driver, only having a fixed table, rejects this because it's off by one Hz
• other mclk freqs like 12Mhz or 12.5Mhz yield wrong pitches and distortion/aliasing (unclear why)
• so we add support for 12279999 Hz in the tlv320aic31xx and it's fine
• tested with hearing tests of 440 Hz sine tones and comparing to other devices