x86: suppress duplicate symbol warnings for CONFIG_GCOV

x86: suppress duplicate symbol warnings for CONFIG_GCOV

There are quite a few of these, and as the option is a development one
only, duplicate symbol names should not be an issue there. In other
environments allow the user to control this, unless Live patching is
enabled.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>