add gcc bfin patch

toolchain/gcc/patches/6.1.0/disable-dwarf.bfin

@@ -0,0 +1,12 @@
+diff -Nur gcc-6.1.0.orig/libgcc/config.host gcc-6.1.0/libgcc/config.host
+--- gcc-6.1.0.orig/libgcc/config.host	2016-02-26 21:02:28.000000000 +0100
++++ gcc-6.1.0/libgcc/config.host	2016-04-30 20:49:06.542101273 +0200
+@@ -231,7 +231,7 @@
+   esac
+   ;;
+ *-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu)
+-  tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-eh-dw2-dip t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver t-linux"
++  tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver t-linux"
+   extra_parts="crtbegin.o crtbeginS.o crtbeginT.o crtend.o crtendS.o"
+   if test x$enable_vtable_verify = xyes; then
+     extra_parts="$extra_parts vtv_start.o vtv_end.o vtv_start_preinit.o vtv_end_preinit.o"