lib/tests/kernel-selftests.sh: fix the installation of net selftest

Refer to the commit message of 2a0683be5b4c ("selftests: Introduce
Makefile variable to list shared bash scripts"), the correct way to
install net selftest is "make install TARGETS=net" instead of "make
install -C net"

== before fix ==

linux/tools/testing/selftests$ make install INSTALL_PATH=/usr/bin -C net

rsync -a --copy-unsafe-links config settings /usr/bin/
relative_files=""; for entry in forwarding/lib.sh; do entry_dir=$(readlink -e "$(dirname "$entry")"); entry_name=$(basename "$entry"); relative_dir=${entry_dir#"$SRC_PATH"/}; if [ "$relative_dir" = "$entry_dir" ]; then echo "Error: TEST_INCLUDES entry \"$entry\" not located inside selftests directory ($SRC_PATH)" >&2; exit 1; fi; relative_files="$relative_files $relative_dir/$entry_name"; done; cd  && rsync -aR $relative_files /
rsync: [sender] link_stat "/root/root/linux/tools/testing/selftests/net/forwarding/lib.sh" failed: No such file or directory (2)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1338) [sender=3.2.7]
make: *** [../lib.mk:124: install] Error 23

== after fix ==

linux/tools/testing/selftests$ make install TARGETS=net INSTALL_PATH=/usr/bin

rsync -a --copy-unsafe-links config settings /usr/bin/net/
relative_files=""; for entry in forwarding/lib.sh; do entry_dir=$(readlink -e "$(dirname "$entry")"); entry_name=$(basename "$entry"); relative_dir=${entry_dir#"$SRC_PATH"/}; if [ "$relative_dir" = "$entry_dir" ]; then echo "Error: TEST_INCLUDES entry \"$entry\" not located inside selftests directory ($SRC_PATH)" >&2; exit 1; fi; relative_files="$relative_files $relative_dir/$entry_name"; done; cd /root/linux/tools/testing/selftests && rsync -aR $relative_files /usr/bin/
make[1]: Leaving directory '/root/linux/tools/testing/selftests/net'

Signed-off-by: Yujie Liu <[email protected]>
Signed-off-by: Philip Li <[email protected]>

Author: Yujie-Liu

lib/tests/kernel-selftests.sh

@@ -273,7 +273,7 @@ fixup_net()
 
 	export CCINCLUDE="-I../bpf/tools/include"
 	log_cmd make -j${nr_cpu} -C net 2>&1 || return
-	log_cmd make install INSTALL_PATH=/usr/bin/ -C net 2>&1 || return
+	log_cmd make install TARGETS=net INSTALL_PATH=/usr/bin/ 2>&1 || return
 }
 
 fixup_efivarfs()