mmc: core: export function mmc_do_release_host()

When using mmc_try_claim_host the corresponding release
function is mmc_do_release_host, which then also must
be exported.

Reviewed-by: Jonas Aberg <jonas.aberg@stericsson.com>
Reviewed-by: Sebastian Rasmussen <sebastian.rasmussen@stericsson.com>
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 64e013f..07f27af 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -160,6 +160,7 @@
 
 extern int __mmc_claim_host(struct mmc_host *host, atomic_t *abort);
 extern void mmc_release_host(struct mmc_host *host);
+extern void mmc_do_release_host(struct mmc_host *host);
 extern int mmc_try_claim_host(struct mmc_host *host);
 
 /**