package/riscv64-elf-toolchain: add .hash file

The host-riscv64-elf-toolchain package was missing a hash file, add it now.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit cf2dcaa1ecede670a0bc54841652a0e3bea5c744)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/riscv64-elf-toolchain/riscv64-elf-toolchain.hash

@@ -0,0 +1,2 @@
+# Locally calculated
+sha256  de2bb188300dc38d74103516ce5cfd1060dfd105e8a408e9e3991512cf27285e  riscv64-unknown-elf-toolchain-10.2.0-2020.12.8-x86_64-linux-centos6.tar.gz