staging: vchiq_core: Return -EINTR when bulk transfers are interrupted

staging: vchiq_core: Return -EINTR when bulk transfers are interrupted

Bulk transfers for various VCHIQ modes use mutex_lock_killable() and
wait_for_completion_killable() variations. Currently, -EAGAIN is
returned if these are interrupted by a fatal signal.

-EAGAIN may mislead the caller into thinking the operation can be
retried, while in reality, the process has received a fatal signal
and is terminating. Therefore, we should update the return value to
align with what these killable functions would return, specifically
-EINTR (Interrupted system call).

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Link: https://lore.kernel.org/r/20240918163100.870596-5-umang.jain@ideasonboard.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>