board_f: powerpc: Move prt_83xx_rsr() to private code

This function is called just before checkcpu() on MPX83xx. Move it to the
code for that arch.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc83xx/cpu.c b/arch/powerpc/cpu/mpc83xx/cpu.c
index c87f0fd..cb82621 100644
--- a/arch/powerpc/cpu/mpc83xx/cpu.c
+++ b/arch/powerpc/cpu/mpc83xx/cpu.c
@@ -33,6 +33,7 @@
 	u32 pvr = get_pvr();
 	u32 spridr;
 	char buf[32];
+	int ret;
 	int i;
 
 	const struct cpu_type {
@@ -61,6 +62,10 @@
 
 	immr = (immap_t *)CONFIG_SYS_IMMR;
 
+	ret = prt_83xx_rsr();
+	if (ret)
+		return ret;
+
 	puts("CPU:   ");
 
 	switch (pvr & 0xffff0000) {