Holding the BKL in input_open_file seems pointless because it does not
protect against updates of input_table, and all open functions from the
underlying drivers have proper mutex locking.
This makes input_open_file take the input_mutex when accessing
the table and no lock when calling into the lower function.
Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>