msm_fb: HDMI: MUX Enable HDMI if no MHL

With integrated MHL support on some targets such
as 8x30 FLUID, a MUX needs to be configured explicitly to select
between MHL and HDMI. This change selects the HDMI option
when MHL is disabled.

Change-Id: I55bed8bbfd3f86be2be1e4a61526849a2ec51693
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>