STM32H legacy driver: change parameter to pucGetRXBuffer()

This issue was reported on the FreeRTOS forum by userhttps://github.com/kzorer.
This is the essential change:

    /* Subtracted 'ipBUFFER_PADDING', which is the size of the meta data. */
    pucBuffer = pucGetRXBuffer( ETH_RX_BUF_SIZE - ipBUFFER_PADDING  );
    configASSERT( pucBuffer != NULL );

This was a result of an earlier patch that repair a vulnerability.

Test Steps

Create an application that connects to the Ethernet and try anything, send it a an ICMP ping message and it will fail. It went wrong in this test:

NetworkBufferDescriptor_t * pxGetNetworkBufferWithDescriptor( size_t xRequestedSizeBytes,
                                                              TickType_t xBlockTimeTicks )
{
    if( ( xNetworkBufferSemaphore != NULL ) &&
        ( xRequestedSizeBytes <= uxMaxNetworkInterfaceAllocatedSizeBytes ) )
    {
    /* xRequestedSizeBytes was too big, it included the buffer meta data.

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

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