Internal heap was occupying the region straight after .data up to
HEAP_REGION1. The issue with this is if static allocation is large,
we'll end up with too little memory left for the internal heap.
Moving it to the beginning of region 2 gives us more room to play with.
Signed-off-by: Abdelatif Guettouche <abdelatif.guettouche@espressif.com>