[OpenMP] Fix using the target ID when using the new driver

AMDGPU sometimes uses a novel formatting for their offloading
architecture called the target id. This merges the attributes and the
architecture name into a single string. Previously, we were passing this
as the canonical architecture name. This caused the linker wrapper to
fail to find relevant libraries and then pass an incalid CPU name. This
patch changes the handling in the offload packager to handle the
canonical architecture and then extract the features.

Reviewed By: yaxunl

Differential Revision: https://reviews.llvm.org/D150998