Disable CGO on riscv64

Its not supported yet

(From OE-Core rev: ecec793f36545cab9c14a64b267b1d4f694d0323)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/go.bbclass

@@ -53,6 +53,7 @@ GOTOOLDIR_class-native = "${STAGING_LIBDIR_NATIVE}/go/pkg/tool/${BUILD_GOTUPLE}"
 export GOTOOLDIR
 
 export CGO_ENABLED ?= "1"
+export CGO_ENABLED_riscv64 = "0"
 export CGO_CFLAGS ?= "${CFLAGS}"
 export CGO_CPPFLAGS ?= "${CPPFLAGS}"
 export CGO_CXXFLAGS ?= "${CXXFLAGS}"