If we playback the 8KHz FS audio with the 256 mclk_fs, we need the
mclk = 256 * 8000 = 2.048MHz, the frac div is 594 / 2.048 = 290,
the frac div value 0x00809015 set to the CRU_CLKSEL7_CON will cause
to hang.

We increase the mclk_fs to 512, will get the mclk = 512 * 8000 =
4.096MHz, use 0x01009015 instead of 0x00809015 to work around this
issue. We will keep tracking it.
Signed-off-by: NXing Zheng <zhengxing@rock-chips.com>
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>