PCI: mt7621: Fix string truncation in mt7621_pcie_parse_port()

PCI: mt7621: Fix string truncation in mt7621_pcie_parse_port()

The following warning appears when driver is compiled with W=1.

CC      drivers/pci/controller/pcie-mt7621.o
drivers/pci/controller/pcie-mt7621.c: In function ‘mt7621_pcie_probe’:
drivers/pci/controller/pcie-mt7621.c:228:49: error: ‘snprintf’ output may
be truncated before the last format character [-Werror=format-truncation=]
228 |         snprintf(name, sizeof(name), "pcie-phy%d", slot);
    |                                                 ^
drivers/pci/controller/pcie-mt7621.c:228:9: note: ‘snprintf’ output between
10 and 11 bytes into a destination of size 10
228 |         snprintf(name, sizeof(name), "pcie-phy%d", slot);
    |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Clean this up increasing destination buffer one byte.

[kwilczynski: commit log]
Closes: https://lore.kernel.org/linux-pci/20240110212302.GA2123146@bhelgaas/T/#t
Link: https://lore.kernel.org/linux-pci/20240111082704.2259450-1-sergio.paracuellos@gmail.com
Reported-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>