MIPS: Octeon: Fix DT pruning bug with pip ports

During the pruning of the device tree octeon_fdt_pip_iface() is called
for each PIP interface and every port up to the port count is removed
from the device tree. However, the count was set to the return value of
cvmx_helper_interface_enumerate() which doesn't actually return the
count but just returns zero on success. This effectively removed *all*
ports from the tree.

Use cvmx_helper_ports_on_interface() instead to fix this. This
successfully restores the 3 ports of my ERLite-3 and fixes the "kernel
assigns random MAC addresses" issue.

Signed-off-by: Faidon Liambotis <paravoid@debian.org>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5587/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/cavium-octeon/octeon-platform.c

@@ -334,9 +334,10 @@ static void __init octeon_fdt_pip_iface(int pip, int idx, u64 *pmac)
 	char name_buffer[20];
 	int iface;
 	int p;
-	int count;
+	int count = 0;
 
-	count = cvmx_helper_interface_enumerate(idx);
+	if (cvmx_helper_interface_enumerate(idx) == 0)
+		count = cvmx_helper_ports_on_interface(idx);
 
 	snprintf(name_buffer, sizeof(name_buffer), "interface@%d", idx);
 	iface = fdt_subnode_offset(initial_boot_params, pip, name_buffer);