bnx2x: avoid atomic allocations during initialization

During initialization bnx2x allocates significant amounts of memory
(for rx data, rx SGEs, TPA pool) using atomic allocations.

I received a report where bnx2x failed to allocate SGEs and it had
to fall back to TPA-less operation.

Let's use GFP_KERNEL allocations during initialization, which runs
in process context. Add gfp_t parameters to functions that are used
both in initialization and in the receive path.

Use an unlikely branch in bnx2x_frag_alloc() to avoid atomic allocation
by netdev_alloc_frag(). The branch is taken several thousands of times
during initialization, but then never more. Note that fp->rx_frag_size
is never greater than PAGE_SIZE, so __get_free_page() can be used here.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>