powerpc/32: Fix crash during static key init

We cannot do those initializations from apply_feature_fixups() as
this function runs in a very restricted environment on 32-bit where
the kernel isn't running at its linked address and the PTRRELOC()
macro must be used for any global accesss.

Instead, split them into a separtate steup_feature_keys() function
which is called in a more suitable spot on ppc32.

Fixes: 309b315b6e ("powerpc: Call jump_label_init() in apply_feature_fixups()")
Reported-and-tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/lib/feature-fixups.c

@@ -188,7 +188,10 @@ void __init apply_feature_fixups(void)
 			  &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
 #endif
 	do_final_fixups();
+}
 
+void __init setup_feature_keys(void)
+{
 	/*
 	 * Initialise jump label. This causes all the cpu/mmu_has_feature()
 	 * checks to take on their correct polarity based on the current set of