cryptfs: Add error messages when remove dm-crypt device is failed

We do not know what happened if remove dm-crypt device is failed, so
the error status added is useful to debug failed ioctl.

Change-Id: I49be91b9087ef2a213a706dd6b2a07eb6dafe6e6
Signed-off-by: Yue Hu <zbestahu@gmail.com>
1 file changed