net/sfc: fix type of opaque pointer in perf profile handler

The 'opaque' pointer in handler function is the last argument
of sfc_kvargs_process() function and it is pointer to the adapter
'evq_flags' that has a uint32_t type. So 'value' must be pointer
to uint32_t.

Fixes: c22d3c508e0c ("net/sfc: support parameter to choose performance profile")
Cc: stable@dpdk.org
Signed-off-by: Roman Zhukov <roman.zhukov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>