modpost: use sym_get_data() to get module device_table data

Use sym_get_data() to replace the long code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

scripts/mod/modpost.h

@@ -187,6 +187,7 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen);
 /* from modpost.c */
 char *read_text_file(const char *filename);
 char *get_line(char **stringp);
+void *sym_get_data(const struct elf_info *info, const Elf_Sym *sym);
 
 enum loglevel {
 	LOG_WARN,