nfp: fix absolute rtsym handling in debug dump

In TLV-based ethtool debug dumps, don't do a CPP read for absolute
rtsyms, use the addr field in the symbol table directly as the value.

Without this fix rtsym gro_release_ring_0 is 4 bytes of zeros.
With this fix the correct value, 0x0000004a 0x00000000 is reported.

The values may be read using ethtool debug level 2.
 # ethtool -W <netdev> 2
 # ethtool -w <netdev> data dump.dat

Fixes: e1e798e3

 ("nfp: dump rtsyms")
Signed-off-by: Carl Heymann <carl.heymann@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>