adv7481: Add early error returns

In boards without adv7481 chip present, there is a huge
boot time impact due to long time taken by probe failure
because of I2C communication failures. Add early returns
in case of error, to minimize the impact.

Change-Id: I74643ec8e35e16ba93b795cccd8c709c8e530889
Signed-off-by: Suprith Malligere Shankaregowda <supgow@codeaurora.org>