ARC: Disable --gc-sections

It is a known problem (see STAR 9000656506) that ld option --gc-sections
cause failed assertions for ARC. Until the root cause will be resolved,
disable --gc-sections.

Signed-off-by: Anton Kolesov <anton.kolesov@synopsys.com>
Merge pull request #22 from anthony-kolesov/disable-gc-sections

ARC: Disable --gc-sections