net: libwx: fix the creation of page_pool

net: libwx: fix the creation of page_pool

'rx_ring->size' means the count of ring descriptors multiplied by the
size of one descriptor. When increasing the count of ring descriptors,
it may exceed the limit of pool size.

[ 864.209610] page_pool_create_percpu() gave up with errno -7
[ 864.209613] txgbe 0000:11:00.0: Page pool creation failed: -7

Fix to set the pool_size to the count of ring descriptors.

Fixes: 850b971110b2 ("net: libwx: Allocate Rx and Tx resources")
Cc: stable@vger.kernel.org
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/434C72BFB40E350A+20250625023924.21821-1-jiawenwu@trustnetic.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>