video: fbdev: neofb: Fix set but not used warning for CursorMem

Fix W=1 warnings by removing unused code

v2:
  - Updated subject (Lee)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Evgeny Novikov <novikov@ispras.ru>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Lee Jones <lee.jones@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201128224114.1033617-16-sam@ravnborg.org