powerpc: Don't include asm/setup.h in asm/machdep.h

asm/machdep.h doesn't need asm/setup.h

Remove it.

Add it directly in files that needs it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3b1dfb19a2c3265fb4abc2bfc7b6eae9261a998b.1654966508.git.christophe.leroy@csgroup.eu