drm: msm: Fix kernel panic error

HDMI non_pluggable is only specific to auto dts setting.
If it's not presented in other products' dts entry, as
hdmi is null, calling hdmi_i2c_destroy() will cause null
pointer access and kernel panic would happen. So remove
the calling of such code.

Change-Id: I37bdd281f5b231831ae87f2ba344b01d3cdfaef7
Signed-off-by: Rahul Sharma <rahsha@codeaurora.org>