spi: Don't call spi_get_gpio_descs() before device name is set

Move code calling spi_get_gpio_descs() to happen after ctlr->dev's
name is set in order to have proper GPIO consumer names.

Before:

cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-31, parent: platform/40049000.gpio, vf610-gpio:
 gpio-6   (                    |regulator-usb0-vbus ) out lo

gpiochip1: GPIOs 32-63, parent: platform/4004a000.gpio, vf610-gpio:
 gpio-36  (                    |scl                 ) in  hi
 gpio-37  (                    |sda                 ) in  hi
 gpio-40  (                    |(null) CS1          ) out lo
 gpio-41  (                    |(null) CS0          ) out lo ACTIVE LOW
 gpio-42  (                    |miso                ) in  hi
 gpio-43  (                    |mosi                ) in  lo
 gpio-44  (                    |sck                 ) out lo

After:

cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-31, parent: platform/40049000.gpio, vf610-gpio:
 gpio-6   (                    |regulator-usb0-vbus ) out lo

gpiochip1: GPIOs 32-63, parent: platform/4004a000.gpio, vf610-gpio:
 gpio-36  (                    |scl                 ) in  hi
 gpio-37  (                    |sda                 ) in  hi
 gpio-40  (                    |spi0 CS1            ) out lo
 gpio-41  (                    |spi0 CS0            ) out lo ACTIVE LOW
 gpio-42  (                    |miso                ) in  hi
 gpio-43  (                    |mosi                ) in  lo
 gpio-44  (                    |sck                 ) out lo

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>