OMAP4: DPLL cascading: Don't limit DPLL cascading to 4430 by default

By default DPLL cascading was enabled only for OMAP4430. This patch enable DPLL
cascading for OMAP44XX by default.

Change-Id: I0533dcd8ff9d2644177cbeaa607b85de510b1e6b
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>