ucc_geth: Remove UGETH_FILTERING dead code

The code appears to be dead: nobody call these functions, plus build
breaks when UGETH_FILTERING is enabled:

ucc_geth.c:1848: warning: 'struct enet_addr' declared inside parameter list
ucc_geth.c:1848: warning: its scope is only this definition or declaration, which is probably not what you want
ucc_geth.c: In function 'ugeth_82xx_filtering_get_match_addr_in_hash':
ucc_geth.c:1856: error: dereferencing pointer to incomplete type
ucc_geth.c:1874: error: dereferencing pointer to incomplete type
ucc_geth.c:1877: warning: return from incompatible pointer type
ucc_geth.c: At top level:
ucc_geth.c:1885: warning: 'struct enet_addr' declared inside parameter list
ucc_geth.c: In function 'ugeth_82xx_filtering_add_addr_in_hash':
ucc_geth.c:1894: error: dereferencing pointer to incomplete type
ucc_geth.c:1909: warning: passing argument 2 of 'ugeth_82xx_filtering_get_match_addr_in_hash' from incompatible pointer type
ucc_geth.c:1909: warning: assignment from incompatible pointer type
ucc_geth.c:1918: error: dereferencing pointer to incomplete type
ucc_geth.c: At top level:
ucc_geth.c:1928: warning: 'struct enet_addr' declared inside parameter list
ucc_geth.c: In function 'ugeth_82xx_filtering_clear_addr_in_hash':
ucc_geth.c:1947: warning: passing argument 2 of 'ugeth_82xx_filtering_get_match_addr_in_hash' from incompatible pointer type
ucc_geth.c:1947: warning: assignment from incompatible pointer type
ucc_geth.c:1954: error: dereferencing pointer to incomplete type
ucc_geth.c: At top level:
ucc_geth.c:2060: warning: 'struct enet_addr' declared inside parameter list
ucc_geth.c: In function 'ugeth_82xx_filtering_add_addr_in_paddr':
ucc_geth.c:2064: error: dereferencing pointer to incomplete type
ucc_geth.c:2073: error: dereferencing pointer to incomplete type
ucc_geth.c:2075: warning: passing argument 2 of 'hw_add_addr_in_paddr' from incompatible pointer type
make[2]: *** [ucc_geth.o] Error 1

The code is there since the driver was merged, and nobody seem to be
interested in fixing or actually using it. If we ever want the
filtering support, we can always revert the patch and fix it, but so
far it just draws reader's attention.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>