test: increase FVP Trusted SRAM where necessary

The TF-A configurations used by some tests require a larger Trusted SRAM
than the 256KB default. This increases the Trusted SRAM of these tests
to 384KB.

Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: If9a09d32472d8db78bd375da343a8feca6f82044
diff --git a/tf_config/fvp-tspd-tbb-mbedtls-ecdsa-dualroot b/tf_config/fvp-tspd-tbb-mbedtls-ecdsa-dualroot
index 2ed6144..50f274f 100644
--- a/tf_config/fvp-tspd-tbb-mbedtls-ecdsa-dualroot
+++ b/tf_config/fvp-tspd-tbb-mbedtls-ecdsa-dualroot
@@ -9,3 +9,4 @@
 SPD=tspd
 TF_MBEDTLS_KEY_ALG=rsa+ecdsa
 TRUSTED_BOARD_BOOT=1
+FVP_TRUSTED_SRAM_SIZE=384