NetworkPkg/HttpBootDxe: Add RISC-V architecture for EDK2 CI.

NetworkPkg/HttpBootDxe: Add RISC-V architecture for EDK2 CI.

Add RISC-V architecture for EDK2 CI testing.

BZ:2562:
https://bugzilla.tianocore.org/show_bug.cgi?id=2562

Signed-off-by: Abner Chang <abner.chang@hpe.com>
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Gilbert Chen <gilbert.chen@hpe.com>
Cc: Daniel Schaefer <daniel.schaefer@hpe.com>