em(4) & DEFAULT_ITR

[Eugene Grosbein]

Hi!

em(4) driver got new sysctl for 'itr' moderation register recently in head and stable/9.
Previously, it used the macro DEFAULT_ITR for it.

It seems for me, however, revision 250414 that brought this new feature
was quite incomplete: driver still uses DEFAULT_ITR macro instead of sysctl value
in the em_initialize_receive_unit() function. Isn't it a bug?

And there is no loader tunable like in igb(4) to make a default
to eliminate a need of extra reset of each adapter at sysctl time.

And it is more convenient to set it in terms of "maximum interrupt per second"
than as 'usec/4' unit timeouts, please :-)

Eugene Grosbein