ARM: 6077/1: ux500: add SOC Kconfig variables

This adds the different config options for SoCs DB8500 and DB5500 and
refines the SoC/CPU detection code to support the DB5500 as well via
these.  The selection between DB5500 and DB8500 is currently a simple
compile-time choice.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>