treewide: Fix typos in various Kconfig

Correct spelling typo within various Kconfig.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 9bf10e7..4905795 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -541,7 +541,7 @@
 	  If unsure, say Y.
 
 config MMC_DW_EXYNOS
-	tristate "Exynos specific extentions for Synopsys DW Memory Card Interface"
+	tristate "Exynos specific extensions for Synopsys DW Memory Card Interface"
 	depends on MMC_DW
 	select MMC_DW_PLTFM
 	help