Remove duplicate CLEARMACINT and return error code at DELMACDYN.

CLEARMACINT duplicated DELMACDYN.
As fdb_del and fdb_cleanup_* functions return hit number in fdb, adapt the
return value of DELMACDYN.
Note: Recompile the kernel or copy ./include/linux/net_switch.h to
/usr/src/kernels/.../include/linux and reinsert the switch module.

Signed-off-by: Andreea Hodea <hodea_andreea@yahoo.com>