drm/mgag200: Remove mgag200_cursor.c

drm/mgag200: Remove mgag200_cursor.c

Support for HW cursors got remove by commit aea0f2b2307d ("drm/mgag200:
Remove HW cursor") Apparently the source file was not deleted. Removed
it now.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Fixes: aea0f2b2307d ("drm/mgag200: Remove HW cursor")
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Emil Velikov <emil.velikov@collabora.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Allison Randal <allison@lohutok.net>
Cc: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Cc: "José Roberto de Souza" <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200605135803.19811-3-tzimmermann@suse.de