Fix several annotations in assembly files on PPC32.

[Sathvika Vasireddy: Changed subject line and removed Kconfig change to
 enable objtool, as it is a part of "objtool/powerpc: Enable objtool to
 be built on ppc" patch in this series.]
Tested-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: NChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: NSathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-7-sv@linux.ibm.com