Build: Turn off BL2 for NXP LPCxpresso55S69 platform

Turn off BL2 temporary, since there is an oversize issue [1]

[1]: https://linaro.atlassian.net/browse/TFC-194

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: If0d63a0f1f7af99019d38cd58dae1293eacf73db
1 file changed