Instead of directly using malloc, use FreeRTOS provided malloc API.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

FreeRTOS TCP/IP stack recommends `heap_4` and `BufferAllocation_2`.
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/tree/V4.0.0-appsec#note

Since FreeRTOS manages the heap, set Mbed TLS memory APIs to use
FreeRTOS heap APIs (mbedtls_platform_set_calloc_free).

In addition, reduce allocated heap size from `0x000b0000` to
`0x00000400`, since FreeRTOS manages heap when `heap_4` configuration is
selected. Ideally, heap size should be 0, however, GNU expects linker
symbol `end` to be available. Hence, set it to `0x400`.

Also, set the FreeRTOS config `configAPPLICATION_ALLOCATED_HEAP` to 0,
indicating FreeRTOS allocates the heap based on `configTOTAL_HEAP_SIZE`
(720896 bytes).

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

The socket creation is part of
`Middleware/ARM/IoT_VSocket-lib/AVH/interface/vsocket/iot_socket.c` and
hence `socket_startup.c` is redundant. In addition, `socket_startup()`
always returns 0.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

The system event helper library provides system event management, so
that the tasks can wait on the required system event to happen.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Add a CMake variable `CONNECTIVITY_STACK`, so that the application can
select a network stack from the supported network stacks.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Since we are integrating latest version of FreeRTOS TCP/IP stack which
relies on FreeRTOS kernel, ensure that we are using the latest released
version of FreeRTOS kernel which is `V10.6.1`.

In addtion, fix a typo and remove unused macro from `FreeRTOSConfig.h`.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Added support for FreeRTOS TCP/IP stack and made it the default choice
of network stack.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Added support for choosing either ecosystem FVP or Arm virtual hardware
FVP running in the AMI to the `run.sh` script. The ecosystem FVP is used
by default.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

With the addition of support for FreeRTOS TCP/IP stack, in addition to
Arm Virtual Hardware using Amazon Machine Images, Arm FRI can now run
ecosystem FVPs.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>

Provide justification for setting `configTICK_RATE_HZ` to `100` to
simulate scheduler polling rate of `1000 Hz` or 1 tick per second.

Signed-off-by: Devaraj Ranganna <devaraj.ranganna@arm.com>