ARM: DRA7: Reuse io tables and add a new .init_early

The IO descriptor tables for DRA7 are a complete reuse from OMAP5.
A new dra7xx_init_early() does the base address inits.

Signed-off-by: R Sricharan <r.sricharan@ti.com>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>