net: stmmac: mmc_core: Drop interrupt registers from stats

The MMC IPC interrupt status and interrupt mask registers are
of little use as Ethernet statistics, but incrementing counters
based on the current interrupt and interrupt mask registers
makes them actively misleading.

For example, if the interrupt mask is set to 0x08420842,
the current code will increment by that amount each iteration,
leading to the following sequence of nonsense:

mmc_rx_ipc_intr_mask: 969816526
mmc_rx_ipc_intr_mask: 1108361744

These registers have been included in the Ethernet statistics
since the first version of MMC back in 2011 (commit 1c901a46

).
That commit also mentions the MMC interrupts as
"something to add later (if actually useful)".

If the registers are actually useful, they should probably
be part of the Ethernet register dump instead of statistics,
but for now, drop the counters for mmc_rx_ipc_intr and
mmc_rx_ipc_intr_mask completely.

Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240223-stmmac_stats-v3-1-5d483c2a071a@axis.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>