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-dualroot b/tf_config/fvp-tspd-tbb-mbedtls-dualroot
index 0cd52a5..ede1b48 100644
--- a/tf_config/fvp-tspd-tbb-mbedtls-dualroot
+++ b/tf_config/fvp-tspd-tbb-mbedtls-dualroot
@@ -6,3 +6,4 @@
 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem
 SPD=tspd
 TRUSTED_BOARD_BOOT=1
+FVP_TRUSTED_SRAM_SIZE=384