powerpc: Move epapr_paravirt_early_init() to early_init_devtree()

The function is called by both 32-bit and 64-bit early setup right
after early_init_devtree(). All it does is run yet another early
DT parser which is precisely what early_init_devtree() is about,
so move it in there.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>