octeontx2-pf: Simplify the receive buffer size calculation

This patch separates the logic of configuring hardware
maximum transmit frame size and receive frame size.
This simplifies the logic to calculate receive buffer
size and using cqe descriptor of different size.
Also additional size of skb_shared_info structure is
allocated for each receive buffer pointer given to
hardware which is not necessary. Hence change the
size calculation to remove the size of
skb_shared_info. Add a check for array out of
bounds while adding fragments to the network stack.

Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>