drivers/video/backlight/jornada720_*.c: make needlessly global symbols static

The following symbols are needlessly defined global: jornada_bl_init,
jornada_bl_exit, jornada_lcd_init, jornada_lcd_exit.

Make them static.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>