fix: increase TSRAM to 384KB for fvp-tbb-mbedtls-tsp-async-irq2el3-no-cohmem build

This helps to resolve the following build fail:

aarch64-none-elf-ld.bfd: BL31 progbits has exceeded its limit. Consider disabling some features.
make: *** [Makefile:1497: /home/buildslave/workspace/tf-a-builder/trusted-firmware-a/build/fvp/debug/bl31/bl31.elf] Error 1

Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Change-Id: Ib04e0a7d6448a5c60fceac62b07ddbecb16d015d
diff --git a/tf_config/fvp-tbb-mbedtls-tsp-async-irq2el3-no-cohmem b/tf_config/fvp-tbb-mbedtls-tsp-async-irq2el3-no-cohmem
index 2305555..261be28 100644
--- a/tf_config/fvp-tbb-mbedtls-tsp-async-irq2el3-no-cohmem
+++ b/tf_config/fvp-tbb-mbedtls-tsp-async-irq2el3-no-cohmem
@@ -1,6 +1,7 @@
 ARM_ROTPK_LOCATION=devel_rsa
 CROSS_COMPILE=aarch64-none-elf-
 GENERATE_COT=1
+FVP_TRUSTED_SRAM_SIZE=384
 NS_TIMER_SWITCH=1
 PLAT=fvp
 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem