bus: fsl-mc: declare fsl_mc_bus_dpdbg_type static

bus: fsl-mc: declare fsl_mc_bus_dpdbg_type static

Fix following sparse warning:

  CHECK   drivers/bus/fsl-mc/fsl-mc-bus.c
drivers/bus/fsl-mc/fsl-mc-bus.c:435:26: warning: symbol 'fsl_mc_bus_dpdbg_type' was not declared. Should it be static?

fsl_mc_bus_dpdbg_type is not used outside of fsl-mc-bus.c

Remove the EXPORT_SYMBOL and declare it static.

Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Link: https://patch.msgid.link/628c49881b3a1df76cfd2f8fd2aad976692a465a.1768566053.git.chleroy@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>