drm/edid: Rename local variable block to edid

The "block" variable points to the entire edid, not individual blocks
despite it being named such.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161017083514.21772-1-chris@chris-wilson.co.uk