spi: mpc512x-psc: Remove redundant code to get bus_num from DT
spi: mpc512x-psc: Remove redundant code to get bus_num from DT

For DT case, spi core will call of_alias_get_id() and set master->bus_num if it
was not set.

Signed-off-by: Axel Lin <b6ffd6973e972cb999e8e535ab74da7fee0c035f@ingics.com>
Tested-by: Gerhard Sittig <c9b3437932eed090edbebd577212b9961ce000fb@denx.de>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs