drivers/sbus/char/envctrl.c: ignore orderly_poweroff return value

drivers/sbus/char/envctrl.c: ignore orderly_poweroff return value

orderly_poweroff() unconditionally returns 0, so remove the dead code that
checks the return value.

A future patch will change the return type to void.

Signed-off-by: Joel Stanley <[email protected]>
Acked-by: David S. Miller <[email protected]>
Cc: Fabian Frederick <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Jeremy Kerr <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>