OvmfPkg/LoongArchVirt: Add Hash2DxeCrypto to satisfy TcpDxe dependency

The TcpDxe driver requires the Hash2 protocol to be available for its
dispatch. On the LoongArchVirt QEMU platform, this protocol was not
previously included, leading to failures when the network stack attempted
to initialize.

Add SecurityPkg/Hash2DxeCrypto to both the DSC and FDF files, ensuring
that the Hash2 protocol is installed and can be consumed by TcpDxe.

Signed-off-by: Qihang Gao <gaoqihang@loongson.cn>