KeyMint VTS: option to skip BOOT_PATCHLEVEL check

The KeyMint spec requires that all generated keys include the
BOOT_PATCHLEVEL for the device.

However, the VTS test sometimes gets run in an environment where this
is not possible; specifically the Trusty QEMU tests don't have the
bootloader -> KeyMint communication that is needed to populate this
information.

Add a command line flag that disables checks for BOOT_PATCHLEVEL to
cope with these scenarios, making sure that it defaults to having the
checks enabled.

Test: VtsAidlKeyMintTargetTest
Change-Id: I215c8a18afbd68af199d49f74b977ad7cac6b805