CP-10220: Enable coverity static analysis for kernel

make is wrapped with 'cov-build' command. This would generate AST which
will be used for analysis, by coverity, at a later stage. This variable is
only defined when 'cov-kernel-dom0' component is built.

For 'kernel-dom0' component, cov-wrap expands to empty string.
CP-9798: Remove use of userspace firmware helper

Userspace firmware loading is removed from recent versions of
udev and causes it to hang.  Because of this, turn off the userspace
firmware helper.

See https://bugzilla.redhat.com/show_bug.cgi?id=997149