mmc: Poll for broken card detection case

Poll for broken card detection case instead of return
no card detected.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index ab0627a..bc29611 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -17,6 +17,11 @@
 	help
 	  Enable write access to MMC and SD Cards
 
+config MMC_BROKEN_CD
+	bool "Poll for broken card detection case"
+	help
+	  If card  detection feature is broken, just poll to detect.
+
 config DM_MMC
 	bool "Enable MMC controllers using Driver Model"
 	depends on DM