anv/pipeline: Stop optimizing for not having a cache

anv/pipeline: Stop optimizing for not having a cache

Before, we were only hashing the shader if we had a shader cache to
cache things in.  This means that if we ever get it wrong, we could end
up trying to cache a shader with an undefined hash.  Since not having a
shader cache is an extremely uncommon case, let's optimize for code
clarity and obvious correctness over avoiding a hash operation.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>