vbe: Allow probing the VBE bootmeth to fail in OS fixup

vbe: Allow probing the VBE bootmeth to fail in OS fixup

This device is created when there are no bootmeths defined in the device
tree. But it cannot be probed without a device tree node.

For now, ignore a probe failure.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Karsten Merker <merker@debian.org>
Suggested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Fixes: 9068460cdd5b ("vbe: Add info about the VBE device to the fwupd node")
Tested-by: Vagrant Cascadian <vagrant@debian.org>
Tested-by: Karsten Merker <merker@debian.org>