msm_fb: display: Adjust overlay VG pipe src params for non-zero x_offset

Adjust overlay VG pipe src params for non-zero x_offset to avoid
overfetching of pixels from the left of x_offset

Change-Id: I00c11ca35879bda7c4c80207549d2f793d6ef2c8
CRs-Fixed: 296185
Signed-off-by: Ravishangar Kalyanam <rkalya@codeaurora.org>