powerpc: Move FW feature probing out of pseries probe()

We move the function itself to pseries/firmware.c and call it along
with almost all other flat device-tree parsers from early_init_devtree()

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Move #ifdefs into the header by providing pseries_probe_fw_features()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/pseries.h

@@ -20,11 +20,6 @@ extern void request_event_sources_irqs(struct device_node *np,
 
 #include <linux/of.h>
 
-extern void __init fw_hypertas_feature_init(const char *hypertas,
-					    unsigned long len);
-extern void __init fw_vec5_feature_init(const char *hypertas,
-					unsigned long len);
-
 struct pt_regs;
 
 extern int pSeries_system_reset_exception(struct pt_regs *regs);