[Patch, microblaze]: Add a small Linux BSP

Provide __init and __fini in linux-crt0.S

This allows the linux version to replace the GCC provided
crti.S which writes to the stack protection registers
(a privileged operation).

Avoid the GCC provided crti.o for elf-linux-gloss

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
[Patch, microblaze]: Adjust exception handler to be weak

User can override exception handler if required.
Change prompted by SVC handler attribute addition in gcc

Signed-off-by:nagaraju <nmekala@xilix.com>
[Patch, configure]: Message that Makefile being deleted on loop for multilibs

should not be set to stderr. Not an error, just info to user

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
[LOCAL]: Add missing declarations for xil_printf to stdio.h

for inclusion in toolchain and use in c++ apps

Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>