net: stmmac: xgmac: Fix L3L4 filter count

net: stmmac: xgmac: Fix L3L4 filter count

Get the exact count of L3L4 filters when the L3L4FNUM field of
HW_FEATURE1 register is >= 8. If L3L4FNUM < 8, then the number of L3L4
filters supported by XGMAC is equal to L3L4FNUM. From L3L4FNUM >= 8
the number of L3L4 filters goes on like 8, 16, 32, ... Current
maximum of L3L4FNUM = 10.

Also, fix the XGMAC_IDDR bitmask of L3L4_ADDR_CTRL register. IDDR
field starts from the 8th bit of the L3L4_ADDR_CTRL register. IDDR[3:0]
indicates the type of L3L4 filter register while IDDR[8:4] indicates
the filter number (0 to 31). So overall 9 bits are used for IDDR
(i.e. L3L4_ADDR_CTRL[16:8]) to address the registers of all the
filters. Currently, XGMAC_IDDR is GENMASK(15,8), causing issues
accessing L3L4 filters above 15 for those XGMACs configured with more
than 16 L3L4 filters.

Signed-off-by: Rohan G Thomas <rohan.g.thomas@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>