man: Update the text for -C option

The default cipher suite has been changed earlier in commit
7772254b62826b894ca629df8c597030a98f4f72, and the manual has been
then updated by commit 50479484a2268d3c9d525ceed729c1faed7244b6,
but it turned out that the description of the -C option was
not affected by the update.

Also, a typo was found as the cipher suites are listed in IPMI v2.0
specification Table 22-20, not 22-19 as stated in the manual.

Signed-off-by: Alexander Amelkin <alexander@amelkin.msk.ru>