powerpc/machdep: Make machine name const

Machine name in struct machdep_calls should never be modified.

Mark it const.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/6cb9865d916231c38401ba34ad1a98c249fae135.1676711562.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/machdep.h

@@ -20,7 +20,7 @@ struct kimage;
 struct pci_host_bridge;
 
 struct machdep_calls {
-	char		*name;
+	const char	*name;
 #ifdef CONFIG_PPC64
 #ifdef CONFIG_PM
 	void		(*iommu_restore)(void);