Optimize load/store of multiple registers

Include const_int offset support for the first memory address in
load_multiple and store_multiple patterns. This results in smaller
and faster code.

Signed-off-by: Dimitar Dimitrov <dinuxbg@gmail.com>
Port newlib and optimize libgcc to use hardware multiplier

- Optimize multiplication libgcc library function by utilizing
  hardware MUL/MAC.
- Initial port of newlib.

Signed-off-by: Dimitar Dimitrov <dinuxbg@gmail.com>
Merge branch 'master' into md5-example

Signed-off-by: Dimitar Dimitrov <dinuxbg@gmail.com>

Conflicts:
	example/pru/Makefile