regulator: msm_gfx_ldo: Fix invalid memory accesses

A few gfx_ldo memory read/write calls use an invalid ldo
base address leading to other corruptions in the system.
Fix this by using the correct LDO base address.

CRs-Fixed: 1078353
Change-Id: I034d473e86b3fe7164d1c9ddad326c9dd77a188f
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>