msm_fb: display: fix hdmi connection crash on 8660

Crash happens because RGB pipe is not completely setup when initializing
the base layer pipe. HDMI crash no longer happens after initializing RGB
pipe correctly.

Change-Id: Iff2e989db95b86fd81afc7e04d12d3d8f099acd7
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>