driver: respect stack frame limit
svec_fpga_app_init() declares too many local buffers that are allocated on the stack.
On some versions of GCC this is detected and reported, causing a warning that is promoted to an error. Example:
svec-core-fpga.c:710:1: error: the frame size of 1968 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
Since apparently it is not a very good idea to increase the stack frame size limit 1, the solution implemented here is to switch to dynimically allocating the biggest buffer (struct resource res).
Signed-off-by: Dimitris Lampridis email@example.com