livepatch: Make livepatch dependent on !TRIM_UNUSED_KSYMS

If TRIM_UNUSED_KSYMS is enabled, all unneeded exported symbols are made
unexported. Two-pass build of the kernel is done to find out which
symbols are needed based on a configuration. This effectively
complicates things for out-of-tree modules.

Livepatch exports functions to (un)register and enable/disable a live
patch. The only in-tree module which uses these functions is a sample in
samples/livepatch/. If the sample is disabled, the functions are
trimmed and out-of-tree live patches cannot be built.

Note that live patches are intended to be built out-of-tree.

Suggested-by: Michal Marek <mmarek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

kernel/livepatch/Kconfig

@@ -10,6 +10,7 @@ config LIVEPATCH
 	depends on SYSFS
 	depends on KALLSYMS_ALL
 	depends on HAVE_LIVEPATCH
+	depends on !TRIM_UNUSED_KSYMS
 	help
 	  Say Y here if you want to support kernel live patching.
 	  This option has no runtime impact until a kernel "patch"