net: dpaa: Fix compilation Warning

net: dpaa: Fix compilation Warning

Remove variables that are defined and incremented but never read.
This issue appeared in network tests[1] as:

	drivers/net/ethernet/freescale/dpaa/dpaa_eth_sysfs.c:38:6: warning: variable 'i' set but not used [-Wunused-but-set-variable]
	38 |         int i = 0;
	   |             ^

Link: https://netdev.bots.linux.dev/static/nipa/870263/13729811/build_clang/stderr
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20240712134817.913756-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>