net: fs_enet: Remove stale prototypes from fsl_soc.c

net: fs_enet: Remove stale prototypes from fsl_soc.c

Commit 3dd82a1ea724 ("[POWERPC] CPM: Always use new binding.")
removed last use of init_fec_ioports() and init_fcc_ioports().

Remove stale prototypes then don't include anymore fs_enet_pd.h
which was only included to provide fs_platform_info structure
for the prototypes.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/f2f2db5dce3242eaa4a2aad6c226ba587fb0f513.1691155347.git.christophe.leroy@csgroup.eu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>