devlink: Change devlink health dump show command to dumpit

devlink: Change devlink health dump show command to dumpit

Although devlink health dump show command is given per reporter, it
returns large amounts of data. Trying to use the doit cb results in
OUT-OF-BUFFER error. This complementary patch raises the DUMP flag in
order to invoke the dumpit cb. We're safe as no existing drivers
implement the dump health reporter option yet.

Fixes: 041e6e651a8e ("devlink: Add devlink health dump show command")
Signed-off-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>