staging: gasket: interrupt: fix the missed eventfd_ctx_put() in gasket_interrupt.c

staging: gasket: interrupt: fix the missed eventfd_ctx_put() in gasket_interrupt.c

gasket_interrupt_set_eventfd() misses to call eventfd_ctx_put() in an
error path. We check interrupt is valid before calling
eventfd_ctx_fdget() to fix it.

There is the same issue in gasket_interrupt_clear_eventfd(), Add the
missed function call to fix it.

Fixes: 9a69f5087ccc ("drivers/staging: Gasket driver framework + Apex driver")
Signed-off-by: Jing Xiangfeng <jingxiangfeng@huawei.com>
Link: https://lore.kernel.org/r/20201112064924.99680-1-jingxiangfeng@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>