LU-9859 libcfs: discard TCD_MAX_TYPES

LU-9859 libcfs: discard TCD_MAX_TYPES

As well as CFS_TCD_TYPE_CNT we have TCD_MAX_TYPES which has a larger
value but a similar meaning.  Discard it and just use
CFS_TCD_TYPE_CNT.

Two places relied on the fact that TCD_MAX_TYPES was larger and so
there would be NULLs at the end of the array.  Change
them to check the array size properly.

Linux-commit: 22627ffa5e7fae0b0b62f90a8f30fc6dae0fff3c

Change-Id: I73a54a409674d3b569bcbaf72e2296209542b74c
Signed-off-by: Mr. NeilBrown <neilb@suse.de>
Reviewed-on: https://review.whamcloud.com/39668
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>