ANDROID: dm: use name_to_dev_t

This patch makes android_verity_ctr() parse its block device string
parameter with name_to_dev_t().  It allows the use of less hardware
related block device reference like PARTUUID for instance.

Change-Id: Idb84453e70cc11abd5ef3a0adfbb16f8b5feaf07
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>