Bug#988231: gnu-efi: package for riscv64

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

After updating the source the only change I needed for packaging was:

--- debian/control      2021-02-04 11:03:03.000000000 +0000
+++ debian/control      2021-05-08 10:27:56.638548003 +0000
@@ -13,7 +13,7 @@
 Homepage: http://sourceforge.net/projects/gnu-efi/

 Package: gnu-efi
-Architecture: any-amd64 any-i386 any-arm64 armhf
+Architecture: any-amd64 any-i386 any-arm64 armhf riscv64
 Depends: ${misc:Depends}
 Description: Library for developing EFI applications
  GNU toolchain for building applications that can run in the environment