qed: avoid possible stack overflow in qed_ll2_acquire_connection

struct qed_ll2_info is rather large, so putting it on the stack
can cause an overflow, as this warning tries to tell us:

drivers/net/ethernet/qlogic/qed/qed_ll2.c: In function 'qed_ll2_start':
drivers/net/ethernet/qlogic/qed/qed_ll2.c:2159:1: error: the frame size of 1056 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

qed_ll2_start_ooo() already uses a dynamic allocation for the structure
to work around that problem, and we could do the same in qed_ll2_start()
as well as qed_roce_ll2_start(), but since the structure is only
used to pass a couple of initialization values here, it seems nicer
to replace it with a different structure.

Lacking any idea for better naming, I'm adding 'struct qed_ll2_conn',
which now contains all the initialization data, and this now simply
gets copied into struct qed_ll2_info rather than assigning all members
one by one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>