spi: davinci: remove unnecessary call to davinci_spi_setup_transfer()

Remove unnecessary call to davinci_spi_setup_transfer() at the end
of davinci_spi_setup().

davinci_spi_setup_transfer() is registered as the setup_transfer
callback for the bitbang layer and is called independently by
the bitbang layer to setup the transfer before it begins.

Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Tested-By: Michael Williamson <michael.williamson@criticallink.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>