powerpc: Remove useless config comment in asm/percpu.h

commit 0db880fc865f ("powerpc: Avoid nmi_enter/nmi_exit in real mode
interrupt.") has a config comment typo, and the #if/#else/#endif section
is small and doesn't nest additional #ifdefs so the comment is useless
and should be removed completely.

Signed-off-by: Jinjie Ruan <[e-mail]>
Suggested-by: Christophe Leroy <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://msgid.link/[e-mail]

arch/powerpc/include/asm/percpu.h

···
 		(static_key_enabled(&__percpu_first_chunk_is_paged.key))
 #else
 #define percpu_first_chunk_is_paged	false
-#endif /* CONFIG_PPC64 && CONFIG_SMP */
+#endif
 
 #include <asm-generic/percpu.h>