UBUNTU: SAUCE: selftests: seccomp: bump up timeout to 5min

UBUNTU: SAUCE: selftests: seccomp: bump up timeout to 5min

 DEBUG| [stdout] # selftests: seccomp: seccomp_benchmark
 DEBUG| [stdout] # net.core.bpf_jit_enable = 1
 DEBUG| [stdout] # net.core.bpf_jit_harden = 0
 DEBUG| [stdout] #
 DEBUG| [stdout] not ok 2 selftests: seccomp: seccomp_benchmark # TIMEOUT 120 seconds

This test can easily fail if the testing environment is a bit
overloaded, so bump up the timeout to 5min to prevent false positive
failures.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>