serial: cpm_uart: Remove stale prototype in powerpc/fsl_soc.c

serial: cpm_uart: Remove stale prototype in powerpc/fsl_soc.c

Commit 0b5cf10691eb ("[POWERPC] 8xx: Convert mpc866ads to the new
device binding.") removed last definition of init_smc_ioports().

Remove it.

And don't include anymore fs_uart_pd.h which is only included to
provide fs_uart_platform_info structure.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/2869659e7faa20b0a506347bc4d1059e22709f19.1691068700.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>