Revert "media: v4l2-fwnode: Return -EINVAL for invalid bus-type"

This reverts commit 2c06ac46 which is
commit 69baf338fc16a4d55c78da8874ce3f06feb38c78 upstream.

It's not really an ABI break, but it is a genksyms break.  It's a
trivial issue this commit is referencing and not work the hack of a
work-around to keep it in here, so just revert the thing.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ie774efb3a30031bbc2b2ca85c398b87d7d065e8e