OvmfPkg/PlatformBootManagerLib: connect consoles unconditionally

OvmfPkg/PlatformBootManagerLib: connect consoles unconditionally

If both ConIn and ConOut exist, but ConIn references none of the PS/2
keyboard, the USB wild-card keyboard, and any serial ports, then
PlatformInitializeConsole() currently allows the boot to proceed without
any input devices at all. This makes for a bad user experience -- the
firmware menu could only be entered through OsIndications, set by a guest
OS.

Do what ArmVirtQemu does already, namely connect the consoles, and add
them to ConIn / ConOut / ErrOut, unconditionally. (The underlying
EfiBootManagerUpdateConsoleVariable() function checks for duplicates.)

The issue used to be masked by the EfiBootManagerConnectAll() call that
got conditionalized in commit 245c643cc8b7.

This patch is best viewed with "git show -b -W".

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Fixes: 245c643cc8b73240c3b88cb55b2911b285a8c10d
Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1577546
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>