video: fbdev: atyfb: mach64_cursor.c: deleted the repeated word

deleted the repeated word 'be' in the comments.

Signed-off-by: lijian <lijian@yulong.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210601012747.38884-1-lijian_8010a29@163.com