ARM: pxa: clean up set_pxa_fb_info

set_pxa_fb_info() has been a long-standing wart in the naming scheme
of the pxa_set_xxx_info() functions.  This renames the function, and
combines set_pxa_fb_parent() with set_pxa_fb_info().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>