qed: reduce maximum stack frame size

clang warns about an overly large stack frame in one function
when it decides to inline all __qed_get_vport_*() functions into
__qed_get_vport_stats():

drivers/net/ethernet/qlogic/qed/qed_l2.c:1889:13: error: stack frame size of 1128 bytes in function '_qed_get_vport_stats' [-Werror,-Wframe-larger-than=]

Use a noinline_for_stack annotation to prevent clang from inlining
these, which keeps the maximum stack usage at around half of that
in the worst case, similar to what we get with gcc.

Fixes: 86622ee7 ("qed: Move statistics to L2 code")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>