arm/dt: 8974-leds: correct address of rgb led bank

With d200 not properly disabled, it will probe and return
num_leds as 0, since it has no children.  This will corrupt
a word of memory.

CRs-fixed: 425593
Change-Id: I48f5e12d063095e3e0918c32f4694bc384af1bac
Signed-off-by: Amy Maloche <amaloche@codeaurora.org>