mmc: sdhci-bcm2835: Use sdhci_pltfm_unregister instead of open coded

This avoid duplicated implementation.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
1 file changed