powerpc: Move Power10 feature PPC_MODULE_FEATURE_P10

Move Power10 feature, PPC_MODULE_FEATURE_P10, definition to be in
arch/powerpc/include/asm/cpufeature.h.

Signed-off-by: Danny Tsen <dtsen@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>