[media] ARM: ap4evb: switch imx074 configuration to default number of lanes

The sh_mobile_csi2 driver will change meaning of the .lanes platform
data field from "bitmask of used lanes" to "number of used lanes."
To avoid a regression during this transition switch ap4evb to rely
on the 2 lane default.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>