modpost: refactor sech_name()

Use sym_get_data_by_offset() helper to get access to the .shstrtab
section data. No functional change is intended because
elf->sechdrs[elf->secindex_strings].sh_addr is 0 for both ET_REL
and ET_EXEC object types.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/mod/modpost.c

@@ -288,18 +288,6 @@ static enum export export_no(const char *s)
 	return export_unknown;
 }
 
-static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
-{
-	return (void *)elf->hdr +
-		elf->sechdrs[elf->secindex_strings].sh_offset +
-		sechdr->sh_name;
-}
-
-static const char *sec_name(struct elf_info *elf, int secindex)
-{
-	return sech_name(elf, &elf->sechdrs[secindex]);
-}
-
 static void *sym_get_data_by_offset(const struct elf_info *info,
 				    unsigned int secindex, unsigned long offset)
 {
@@ -317,6 +305,17 @@ static void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym)
 				      sym->st_value);
 }
 
+static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
+{
+	return sym_get_data_by_offset(info, info->secindex_strings,
+				      sechdr->sh_name);
+}
+
+static const char *sec_name(const struct elf_info *info, int secindex)
+{
+	return sech_name(info, &info->sechdrs[secindex]);
+}
+
 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 
 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)