davinci: minor tnetv107x clock tree fixes

This patch applies the following modifications to the tnetv107x clock tree:

  - reparent tnetv107x usb clocks to usbss

  - mark timer1 as always enabled

  - enable set_rate on pll divider output clocks

  - adjust tnetv107x tsc sysclk rate lower to fix invalid reset defaults

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>