ANDROID: kbuild: fix module linker script flags for LTO

KBUILD_LDS_MODULE didn't exist in 4.19, it was added in upstream commit
10df06385582 ("kbuild: rebuild modules when module linker scripts are
updated"), which means the module-lto.lds linker script is not actually
passed to the linker. Append the flags directly to KBUILD_LDFLAGS_MODULE
instead.

Bug: 151700304
Fixes: 6cea0477 ("ANDROID: kbuild: merge module sections with LTO")
Change-Id: I600db54d2ff9cd4e287913e8ddd463a20741a4a3
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>