config/rx: Make custom linker script optional

Don't add the default linker script if the -r option is present. Signed-off-by: Keith Packard <keithp@keithp.com>

Author: keith-packard

gcc/config/rx/rx.h

@@ -115,7 +115,7 @@
 %{msim:-lsim}%{!msim:-lnosys}	\
 %{fprofile-arcs|fprofile-generate|coverage:-lgcov}	\
 --end-group	\
-%{!T*: %{msim:%Trx-sim.ld}%{!msim:%Trx.ld}}\
+%{!r:%{!T*: %{msim:%Trx-sim.ld}%{!msim:%Trx.ld}}}\
 "
 
 #undef LINK_SPEC