net: mscc: ocelot: calculate vcap offsets correctly for full and quarter entries

When calculating the offsets for the current entry within the row and
placing them inside struct vcap_data, the function assumes half key
entry (2 keys per row).

This patch modifies the vcap_data_offset_get() function to calculate a
correct data offset when the setting VCAP Type-Group of a key to
VCAP_TG_FULL or VCAP_TG_QUARTER.

This is needed because, for example, VCAP ES0 only supports full keys.

Also rename the 'count' variable to 'num_entries_per_row' to make the
function just one tiny bit easier to follow.

Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>