alarmtimer: Change remaining ENOTSUPP to EOPNOTSUPP

Fix backport of commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.

Update backport to change ENOTSUPP to EOPNOTSUPP in
alarm_timer_{del,set}(), which were removed in
f2c45807d3992fe0f173f34af9c347d907c31686 in v4.13-rc1.

Fixes: 65b7a5a3

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>