bnxt_en: extract coredump command line from current task

Tools other than 'ethtool -w' may be used to produce a coredump. For
devlink health, such dumps could even be driver initiated in response
to a health event. In these cases, the kernel thread information will
be placed in the coredump record instead.

v2: use min_t() instead of min() to fix the mismatched type warning

Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>