ARM: davinci: DA850: remove non-existing pll1_sysclk4-7 clocks

DA850: sysclk4-7 only exist for pll0. for pll1 sysclk1-3 exist.

Remove the non-existing clocks.

Signed-off-by: Bas van den Berg <b.van.den.berg.nl@gmail.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>