net: enetc: shorten enetc_setup_xdp_prog() error message to fit NETLINK_MAX_FMTMSG_LEN

NETLINK_MAX_FMTMSG_LEN is currently hardcoded to 80, and we provide an
error printf-formatted string having 96 characters including the
terminating \0. Assuming each %d (representing a queue) gets replaced by
a number having at most 2 digits (a reasonable assumption), the final
string is also 96 characters wide, which is too much.

Reduce the verbiage a bit by removing some (partially) redundant words,
which makes the new printf-formatted string be 73 characters wide with
the trailing newline.

Fixes: 800db2d125c2 ("net: enetc: ensure we always have a minimum number of TXQs for stack")
Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/lkml/[e-mail]/
Signed-off-by: Vladimir Oltean <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/freescale/enetc/enetc.c

···
 	if (priv->min_num_stack_tx_queues + num_xdp_tx_queues >
 	    priv->num_tx_rings) {
 		NL_SET_ERR_MSG_FMT_MOD(extack,
-				       "Reserving %d XDP TXQs does not leave a minimum of %d TXQs for network stack (total %d available)",
+				       "Reserving %d XDP TXQs does not leave a minimum of %d for stack (total %d)",
 				       num_xdp_tx_queues,
 				       priv->min_num_stack_tx_queues,
 				       priv->num_tx_rings);