Blackfin arch: Fix Bug - request lines with peripheral_request_list, but don't get freed with peripheral_free_list

Remove erroneous check_gpio(ident) in peripheral_free()
Reported-by: NMichael McTernan <mmcternan@airvana.com>
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>