idpf: cap maximum Rx buffer size

idpf: cap maximum Rx buffer size

The HW only supports a maximum Rx buffer size of 16K-128. On systems
using large pages, the libeth logic can configure the buffer size to be
larger than this. The upper bound is PAGE_SIZE while the lower bound is
MTU rounded up to the nearest power of 2. For example, ARM systems with
a 64K page size and an mtu of 9000 will set the Rx buffer size to 16K,
which will cause the config Rx queues message to fail.

Initialize the bufq/fill queue buf_len field to the maximum supported
size. This will trigger the libeth logic to cap the maximum Rx buffer
size by reducing the upper bound.

Fixes: 74d1412ac8f37 ("idpf: use libeth Rx buffer management for payload buffer")
Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
Acked-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Madhu Chittim <madhu.chittim@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: David Decotigny <ddecotig@google.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>