net: mvpp2: fix the packet size configuration for 10G

The MVPP22_XLG_CTRL1_FRAMESIZELIMIT define is used as an offset, but is
defined as BIT(0). Updated its name to contains "OFFS" as in offset and
fix its value using the offset value, 0.

Reported-by: Stefan Chulski <stefanc@marvell.com>
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Fixes: 76eb1b1d ("net: mvpp2: set maximum packet size for 10G ports")
Signed-off-by: David S. Miller <davem@davemloft.net>