debian: debci: don't stderr-fail the autopkgtest on modprobe error
debian: debci: don't stderr-fail the autopkgtest on modprobe error

it's optional as tests can be skipped, if mtdram module isn't there

Signed-off-by: Lukas Märdian <e470725f6fcce9ea1b06b91ec715e88542c74455@ubuntu.com>

fwupd/fwupd,fwupd/fwupd,fwupd/fwupd,fwupd/fwupd