drm/i915/sdvo: restore i2c adapter config on intel_sdvo_init() failures

SDVOB may be multiplexed with HDMIB. If it's not SDVOB, the same i2c
adapter may be used for HDMIB, with the adjusted config (i.e. with GPIO
bit-banging instead of gmbus). Restore i2c adapter config before error
return from intel_sdvo_init(), letting HDMIB enjoy the joys of gmbus.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>