ANDROID: GKI: Add script to generate symbol protection headers

Called By: KERNEL_SRC/kernel/Makefile if CONFIG_MODULE_SIG_PROTECT=y

Generates headers required by gki_modules.c from symbol lists:

gki_module_protected.h: from android/abi_gki_modules_protected
gki_module_exported.h: from android/abi_gki_modules_exports

Bug: 200082547
Test: Treehugger
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
Change-Id: Ibcc6e6fe0ad6c7850d48f7c0a283c7f9b06e4456
(cherry picked from commit 23cd26aa)