tests/qtest/usb-hcd-ehci-test: Check for EHCI and UHCI HCDs before using them

The devices might not be available in the binary (e.g. when compiling
with "--without-default-devices"), so we have to check before we can
use them.

Message-Id: <20230525081016.1870364-5-thuth@redhat.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
1 file changed