The behavior before this patch would attempt to configure the mux
setting for pins 0 to 27 on PORTD to all be setting 3 for LVDS.  The
LVDS interface actually only uses pins 18 to 27 and not pins 0 to 27
as in the parallel LCD interface.  This patch restricts the
configuration to only the relevant pins 18 to 27 on PORTD.

This was tested on a sun8i A33 tablet with an LVDS screen.  MMC1 has
the capability to use pins 2 to 7 on PORTD and the mux on those pins
was being inadvertently set to setting 3 for MMC functionality which
this patch corrects.

Signed-off-by: Lawrence Yu <lyu@micile.com>
[hdegoede@redhat.com: Only apply this change to A23 / A33]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>