octeontx2-af: Flow control resource management

CN10K MAC block (RPM) and Octeontx2 MAC block (CGX) both supports
PFC flow control and 802.3X flow control pause frames.

Each MAC block supports max 4 LMACS and AF driver assigns same
(MAC,LMAC) to PF and its VFs. As PF and its share same (MAC,LMAC)
pair we need resource management to address below scenarios

1. Maintain PFC and 8023X pause frames mutually exclusive.
2. Reject disable flow control request if other PF or Vfs
   enabled it.

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