octeontx2-pf: Fix lmtst ID used in aura free

Current code uses per_cpu pointer to get the lmtst_id mapped to
the core on which aura_free() is executed. Using per_cpu pointer
without preemption disable causing mismatch between lmtst_id and
core on which pointer gets freed. This patch fixes the issue by
disabling preemption around aura_free.

Fixes: ef6c8da7

 ("octeontx2-pf: cn10K: Reserve LMTST lines per core")
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>