tools/cgget: fix '-m' option usage

tools/cgget: fix '-m' option usage

'-m' is logically an independent option and should not be mixed and
matched with other options and also when used with '-h', help always
takes precedence over other options. Fix both cases of usage with
a bool flag, that gets set when parsing the command line option but
executes only it meets the rules of not mixing with other options.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>