MN10300: Don't cast away the volatile in test_bit()

Don't cast away the volatile in test_bit()'s parameter when we change its type
from const volatile void * so that we can dereference it.

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>