coccinelle: mini_lock: improve performance

Replace <+... ...+> by ... when any.  <+... ...+> is slow, and in some
obscure cases involving backward jumps it doesn't force the unlock to
actually come after the end of the if.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>