powerpc/module_64: Improve restore_r2() return semantics

restore_r2() returns 1 on success, which is surprising for a non-boolean
function.  Change it to return 0 on success and -errno on error to match
kernel coding convention.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/15baf76c271a0ae09f7b8556e50f2b4251e7049d.1674617130.git.jpoimboe@kernel.org

arch/powerpc/kernel/module_64.c

@@ -504,7 +504,7 @@ static int restore_r2(const char *name, u32 *instruction, struct module *me)
 	u32 *prev_insn = instruction - 1;
 
 	if (is_mprofile_ftrace_call(name))
-		return 1;
+		return 0;
 
 	/*
 	 * Make sure the branch isn't a sibling call.  Sibling calls aren't
@@ -512,19 +512,16 @@ static int restore_r2(const char *name, u32 *instruction, struct module *me)
 	 * restore afterwards.
 	 */
 	if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
-		return 1;
+		return 0;
 
 	if (*instruction != PPC_RAW_NOP()) {
 		pr_err("%s: Expected nop after call, got %08x at %pS\n",
 			me->name, *instruction, instruction);
-		return 0;
+		return -ENOEXEC;
 	}
 
 	/* ld r2,R2_STACK_OFFSET(r1) */
-	if (patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC)))
-		return 0;
-
-	return 1;
+	return patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC));
 }
 
 int apply_relocate_add(Elf64_Shdr *sechdrs,
@@ -648,7 +645,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 						strtab + sym->st_name);
 				if (!value)
 					return -ENOENT;
-				if (!restore_r2(strtab + sym->st_name,
+				if (restore_r2(strtab + sym->st_name,
 					       (u32 *)location + 1, me))
 					return -ENOEXEC;
 			} else