pds_core: Clean up init/uninit flows to be more readable

The setup and teardown flows are somewhat hard to follow regarding
pdsc_core_init()/pdsc_dev_init() and their corresponding teardown
flows being in pdsc_teardown(). Improve the readability by adding
new pdsc_core_uninit()/pdsc_dev_unint() functions that mirror their
init counterparts. Also, move the notify and admin qcq allocations
into pdsc_core_init(), so they can be freed in pdsc_core_uninit().

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>