LU-9859 libcfs: rename CFS_TCD_TYPE_MAX to CFS_TCD_TYPE_CNT

LU-9859 libcfs: rename CFS_TCD_TYPE_MAX to CFS_TCD_TYPE_CNT

The possible TCD types are 0, 1, 2.
So the MAX is 2.
The count of the number of types is 3.

CFS_TCD_TYPE_MAX is 3 - obviously wrong.

So rename it to CFS_TCD_TYPE_CNT.

Also there are 2 places where "3" is used rather
than the macro - fix them.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: Ia4ce5fdb3225494f93d1eebd9fddfc15eb2b8316
Reviewed-on: https://review.whamcloud.com/39276
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>