drm/i915: Don't use uninitialized 'ret'

drm/i915: Don't use uninitialized 'ret'

Accidentally removed the 'ret=0' initialization, and thus
we're potentially looking at some stack garbage here.

The whole 'ret = do_stuff; if (!ret) do_other_stuff;' pattern
confuses my brain so let's replace it with the standard
immediate return thing.

Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Fixes: 28a30b45f5e9 ("drm/i915: Convert cdclk to global state")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200207152228.1054-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>