gcc: merge libgcc makefiles for linux/elf targets

gcc/libgcc/config/riscv/t-linux

@@ -1,3 +0,0 @@
-LIB2ADD += $(srcdir)/config/riscv/riscv-fp.c \
-	   $(srcdir)/config/riscv/mul.S \
-	   $(srcdir)/config/riscv/div.S

patches/gcc

@@ -211,11 +211,11 @@
  	extra_parts="$extra_parts crtbegin.o crtend.o crtbeginS.o crtendS.o crtbeginT.o ecrti.o ecrtn.o ncrti.o ncrtn.o"
  	;;
 +riscv32*-*-linux*)
-+	tmake_file="${tmake_file} riscv/t-fpbit riscv/t-dpbit riscv/t-tpbit riscv/t-linux riscv/t-linux32"
++	tmake_file="${tmake_file} riscv/t-fpbit riscv/t-dpbit riscv/t-tpbit riscv/t-elf riscv/t-elf32"
 +	extra_parts="$extra_parts crtbegin.o crtend.o crti.o crtn.o crtendS.o crtbeginT.o"
 +	;;
 +riscv*-*-linux*)
-+	tmake_file="${tmake_file} riscv/t-fpbit riscv/t-dpbit riscv/t-tpbit riscv/t-linux"
++	tmake_file="${tmake_file} riscv/t-fpbit riscv/t-dpbit riscv/t-tpbit riscv/t-elf"
 +	extra_parts="$extra_parts crtbegin.o crtend.o crti.o crtn.o crtendS.o crtbeginT.o"
 +	;;
 +riscv*-*-*)