memory-failure: change type of action_result's param 3 to enum

memory-failure: change type of action_result's param 3 to enum

Change type of action_result's param 3 to enum for type consistency,
and rename mf_outcome to mf_result for clearly.

Signed-off-by: Xie XiuQi <[email protected]>
Acked-by: Naoya Horiguchi <[email protected]>
Cc: Chen Gong <[email protected]>
Cc: Jim Davis <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Tony Luck <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>