lib: Add ASan support to ramstage on x86 arch

This patch adds address sanitizer module to the library and reserves
a linker section representing the shadow region for ramstage. Also,
it adds an instruction to initialize shadow region on x86
architecture when ramstage is loaded.

Change-Id: Ica06bd2be78fcfc79fa888721ed920d4e8248f3b
Signed-off-by: Harshit Sharma <harshitsharmajs@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42496
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>

src/arch/x86/c_start.S

@@ -91,6 +91,10 @@ _start:
 
 	andl	$0xFFFFFFF0, %esp
 
+#if CONFIG(ASAN_IN_RAMSTAGE)
+	call asan_init
+#endif
+
 #if CONFIG(GDB_WAIT)
 	call gdb_hw_init
 	call gdb_stub_breakpoint