dmctl: add report of IMA

This adds an option "ima" in dmctl.

$ dmctl ima product-verity
Targets in the device-mapper table for product-verity:
0-7463768: verity, target_name=verity,target_version=1.9.0,hash_failed=V,verity_version=1,data_device_name=254:4,hash_device_name=254:4,verity_algorithm=sha256,root_digest=d7af9fcb04d184219ba5477b97bb2bbc89fd23a46e03d1dea31d674cc4934769,salt=19d4f2345adfc8b7cc22a3c2f21dd413e5020fc7920a08a33f46f3c61492dfcc,ignore_zero_blocks=y,check_at_most_once=n,verity_mode=restart_on_corruption;

Change-Id: I057970b6c786b3f9a394b4919f5f5115b27cbc08
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>