powerpc/modules: start/end_opd are only needed for ABI v1

The start_opd/end_opd members of struct mod_arch_specific are only
needed for kernels built using ELF ABI v1. Guard them with an ifdef to
save a little bit of space on ELF ABI v2 kernels.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20240812063312.730496-1-mpe@ellerman.id.au

arch/powerpc/include/asm/module.h

@@ -35,9 +35,11 @@ struct mod_arch_specific {
 	bool toc_fixed;			/* Have we fixed up .TOC.? */
 #endif
 
+#ifdef CONFIG_PPC64_ELF_ABI_V1
 	/* For module function descriptor dereference */
 	unsigned long start_opd;
 	unsigned long end_opd;
+#endif
 #else /* powerpc64 */
 	/* Indices of PLT sections within module. */
 	unsigned int core_plt_section;