staging: mt7621-gpio: assign gpio chip custom changes after bgpio_init

bgpio_init function set different data of the gpio chip, like the name.
We want specific name for each bank so to get that not overwritten
move all custom changes after the bgpio_init function call.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>