soc: fsl: qe: drop useless static qualifier

The local variable snum_init has no reason to have static storage duration.

Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Qiang Zhao <qiang.zhao@nxp.com>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Li Yang <leoyang.li@nxp.com>