msm: clock-copper: Fixup lpass clocks to reflect updated documentation

To correctly reflect the LPASS clock hardware, do the following:

1. Remove the max_div setting in the PCM ibit clocks. There
   is no such divider.
2. The I2S external bit branch clocks are not sourced from
   the I2S RCGs. Remove these parent-child relationships.

Change-Id: I849ac51ad028b4d1ce9e3d675ce64afdc99e8c75
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>