board_f: powerpc: Make prt_8260_rsr(), prt_8260_clks() private

Move these two function calls into checkcpu(), which is called on this
arch immediately after these two.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>

arch/powerpc/include/asm/processor.h

@@ -1355,6 +1355,8 @@ void ll_puts(const char *);
 void _nmask_and_or_msr(unsigned long nmask, unsigned long or_val);
 
 int prt_83xx_rsr(void);
+int prt_8260_rsr(void);
+int prt_8260_clks(void);
 
 #endif /* ndef ASSEMBLY*/