spi: bmc2835: use devm_ioremap_resource()

Replace a call to deprecated devm_request_and_ioremap by devm_ioremap_resource.

Found with coccicheck and this semantic patch:
 scripts/coccinelle/api/devm_request_and_ioremap.cocci.

Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>