[POWERPC] Quiet section mismatch in hvc_rtas.c

WARNING: vmlinux.o(.text+0x2066f0): Section mismatch: reference to .init.text:.add_preferred_console (between '.hvc_rtas_console_init' and '.hvc_beat_put_chars')

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>