imx8m: soc.c: demote some printfs to debug

imx8m: soc.c: demote some printfs to debug

Getting

  Found /vpu_g1@38300000 node
  Modify /vpu_g1@38300000:status disabled
  Found /vpu_g2@38310000 node
  Modify /vpu_g2@38310000:status disabled

etc. on the console on every boot is needlessly verbose. Demote the
"Found ..." lines to debug(), which is consistent with other instances
in soc.c.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Peng Fan <peng.fan@nxp.com>