selftests/bpf: Pass sanitizer flags to linker through LDFLAGS

mainline inclusion
from mainline-5.17-rc1
commit 2a2cb45b
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2a2cb45b727b7a1041f3d3d93414b774e66454bb

-------------------------------------------------

When adding -fsanitize=address to SAN_CFLAGS, it has to be passed both
to compiler through CFLAGS as well as linker through LDFLAGS. Add
SAN_CFLAGS into LDFLAGS to allow building selftests with ASAN.
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NHengqi Chen <hengqi.chen@gmail.com>
Link: https://lore.kernel.org/bpf/20211107165521.9240-2-andrii@kernel.org
(cherry picked from commit 2a2cb45b)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>

Conflicts:
	tools/testing/selftests/bpf/Makefile
Signed-off-by: NWang Yufen <wangyufen@huawei.com>

tools/testing/selftests/bpf/Makefile

@@ -26,6 +26,7 @@ CFLAGS += -g -rdynamic -Wall -O2 $(GENFLAGS) $(SAN_CFLAGS)		\
 	  -I$(TOOLSINCDIR) -I$(APIDIR) -I$(OUTPUT)			\
 	  -Dbpf_prog_load=bpf_prog_test_load				\
 	  -Dbpf_load_program=bpf_test_load_program
+LDFLAGS += $(SAN_CFLAGS)
 LDLIBS += -lcap -lelf -lz -lrt -lpthread
 
 # Order correspond to 'make run_tests' order