net/ena: make Tx completion timeout configurable

net/ena: make Tx completion timeout configurable

The default missing Tx completion timeout was set to 5 seconds.
In order to provide users with the interface to control this timeout
to adjust it with the application's watchdog, the device argument for
controlling this value was added.

The parameter is called 'miss_txc_to' and can be modified using the
devargs interface:

  ./app -a <bdf>,miss_txc_to=UINT_NUMBER

This parameter accepts values from 0 to 60 and indicates number of
seconds after which the Tx packet will be considered as missing.

HW hints for the Tx completions timeout were removed to do not overwrite
parameter from the user. Also specifying default Tx completion timeout
value was moved from the configuration to init phase in order to
simplify default value assignment.

Signed-off-by: Michal Krawczyk <mk@semihalf.com>
Reviewed-by: Dawid Gorecki <dgr@semihalf.com>
Reviewed-by: Shai Brandes <shaibran@amazon.com>