linux-wandboard

powerpc: Use rtas_call not call_rtas in CHRP code

The nvram driver imported from the ppc code uses call_rtas, but
rtas_call is the name we are using in merged code (since ppc64 used
that name, and it uses far more RTAS calls than ppc32).

Signed-off-by: Paul Mackerras <paulus@samba.org>