kho: cleanup error handling in kho_populate()

kho: cleanup error handling in kho_populate()

* use dedicated labels for error handling instead of checking if a pointer
  is not null to decide if it should be unmapped
* drop assignment of values to err that are only used to print a numeric
  error code, there are pr_warn()s for each failure already so printing a
  numeric error code in the next line does not add anything useful

Link: https://lkml.kernel.org/r/20260122121757.575987-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>