net:fib_tests.sh in ubuntu_kernel_selftests failed on KVM kernels "Error: Multipath support not enabled in kernel."

[Po-Hsu Lin]

This is not a regression, but a new failure after test case was updated.

With K-kvm 5.19.0-1018.19 last cycle.

 Running 'make run_tests -C net TEST_PROGS=fib_tests.sh TEST_GEN_PROGS='' TEST_CUSTOM_PROGS='''
 make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/net'
 make --no-builtin-rules ARCH=x86 -C ../../../.. headers_install
 make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
   INSTALL ./usr/include
 make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
 TAP version 13
 1..1
 # selftests: net: fib_tests.sh
 #
 # Single path route test
 # Error: Unknown device type.
 not ok 1 selftests: net: fib_tests.sh # exit=2

K-kvm 5.19.0-1019.20 this cycle.
 Running 'make run_tests -C net TEST_PROGS=fib_tests.sh TEST_GEN_PROGS='' TEST_CUSTOM_PROGS='''
 make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/net'
 make --no-builtin-rules ARCH=x86 -C ../../../.. headers_install
 make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
   INSTALL ./usr/include
 make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
 TAP version 13
 1..1
 # selftests: net: fib_tests.sh
 #
 # Single path route test
 # Start point
 # TEST: IPv4 fibmatch [ OK ]
 # TEST: IPv6 fibmatch [ OK ]
 # Nexthop device deleted
 # TEST: IPv4 fibmatch - no route [ OK ]
 # TEST: IPv6 fibmatch - no route [ OK ]
 #
 # Multipath route test
 # Error: Multipath support not enabled in kernel.
 not ok 1 selftests: net: fib_tests.sh # exit=2

This can be found on J-kvm as well.