spi: bcm2835: Remove unnecessary workaround to call gpio_set_value

This should be fixed by commit 4c02cba1
("pinctrl: bcm2835: Fix initial value for direction_output")

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>