fs_mgr: increase verboseness on mount errors

While debugging a mount error, the dmesg output was less
than ideal. The error would be declared but why the mount
failed, and what options were passed was not present. This
patch ensures that the mount options and underlying
errno are printed.

Change-Id: I2b3a2c113149df878c0a8a10ef86fd9e4f909658
1 file changed