[patch, avr] PR31177: Let region text start at __TEXT_REGION_ORIGIN___

[Nick Clifton]

Hi Johann,

> The start of MEMORY region text currently starts hard-coded at 0.
> 
> The linker can produce more exact diagnostics when it knows the exact placements of the memory regions.
> 
> For some old devices, program memory starts at 0x8000, so allow to specify program memory start at __TEXT_REGION_ORIGIN__ similar to how the data region is described.

Approved and applied.

Cheers
   Nick