OvmfPkg/PlatformBootManagerLib: add USB keyboard to ConIn

OvmfPkg/PlatformBootManagerLib: add USB keyboard to ConIn

PlatformInitializeConsole() (called by PlatformBootManagerBeforeConsole())
adds elements of "gPlatformConsole" to ConIn / ConOut / ErrOut (as
requested per element) if at boot at least one of ConIn and ConOut doesn't
exist. This typically applies to new VMs, and VMs with freshly recreated
varstores.

Add a USB keyboard wildcard to ConIn via "gPlatformConsole", so that we
not only bind the PS/2 keyboard. (The PS/2 keyboard is added in
PrepareLpcBridgeDevicePath()). Explicitly connecting the USB keyboard is
necessary after commit 245c643cc8b7.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>