arc: Avoid generating brcc instructions with limm

arc: Avoid generating brcc instructions with limm

BRcc instructions are generated quite late in the compilation
process. These instructions combines a compare with a regular
conditional branch if the result of the compare is not used
anylonger. However, when compiling for size, it is better to avoid
BRcc instructions which are introducing a 32-bit long immediate.

gcc/
2020-12-11  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (arc_reorg): Avoid limm in BRcc.