drm/bridge: megachips-stdpxxxx-ge-b850v3-fw: Fix bridge initialization

Reordering of the device nodes based on unit address resulted in
ge_b850v3_lvds_attach() being called before
ge_b850v3_lvds_ptr->stdp4028_i2c was populated.

This patch moves the drm bridge initialization from
ge_b850v3_lvds_init() to stdp4028_ge_b850v3_fw_probe() ensuring that
ge_b850v3_lvds_ptr->stdp4028_i2c is properly populated.

Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170330081928.8537-1-peter.senna@collabora.com