fvp-tftf.cactus_mm: Increase timeout to 720s

As discussed in https://linaro.atlassian.net/browse/STG-5672.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I1f796b06ddac1ab66e3e5090dbf1da8ec718eae3
1 file changed