kbuild: Ignore __this_module in gen_autoksyms.sh

Module object files can contain an undefined reference to __this_module,
which isn't resolved until we link the final .ko. The kernel doesn't
export this symbol, so ignore it in gen_autoksyms.sh.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Steve Muckle <smuckle@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Ramji Jiyani <ramjiyani@google.com>

scripts/gen_autoksyms.sh

@@ -56,4 +56,7 @@ EOT
 # point addresses.
 sed -e 's/^\.//' |
 sort -u |
+# Ignore __this_module. It's not an exported symbol, and will be resolved
+# when the final .ko's are linked.
+grep -v '^__this_module$' |
 sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"