[media] move i2c files into drivers/media/i2c

Based on a patch from Sylvester Nawrocki

This fixes regression introduced with commmit cb7a01ac,
"[media] move i2c files into drivers/media/i2c".

The linked order affect what drivers will be initialized first, when
they're built-in at Kernel. While there are macros that allow changing
the init order, like subsys_initcall(), late_initcall() & friends,
when all drivers  linked belong to the same subsystem, it is easier
to change the order at the Makefile.

All I2C modules must be linked before any drivers that actually use it,
in order to ensure proper module initialization order.

Also, the core drivers should be initialized before the drivers that use
them.

This patch reorders the drivers init, in order to fulfill the above
requirements.

Reported-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>