config: allow using mold on riscv64

Mold supports 32 and 64 bit RISC-V, but since we only support the 64 bit
version allow using mold on it.

Link: openwrt/openwrt#18575
Signed-off-by: Robert Marko <robimarko@gmail.com>

Author: robimarko

config/Config-build.in

@@ -174,7 +174,7 @@ menu "Global build settings"
 		  Packages can choose to opt-out via setting PKG_BUILD_FLAGS:=no-lto
 
 	config MOLD
-		depends on (aarch64 || arm || i386 || i686 || loongarch64 || m68k || powerpc || powerpc64 || sh4 || x86_64)
+		depends on (aarch64 || arm || i386 || i686 || loongarch64 || m68k || powerpc || powerpc64 || riscv64 || sh4 || x86_64)
 		depends on !GCC_USE_VERSION_11
 		def_bool $(shell, ./config/check-hostcxx.sh 10 2 12)