fbdev: Minor cleanup in WM8505-related code

This replaces the last remaining driver name reference with the
macro for uniformity in wm8505fb.

In addition, the error return path in wmt_ge_rops.c is made more
uniform by getting rid of goto's in remaining places.

Signed-off-by: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>