kmod: convert two call sites to call_usermodehelper_fns()

kmod: convert two call sites to call_usermodehelper_fns()

Both kernel/sys.c && security/keys/request_key.c where inlining the exact
same code as call_usermodehelper_fns(); So simply convert these sites to
directly use call_usermodehelper_fns().

Signed-off-by: Boaz Harrosh <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>