net: sunhme: Fix sbus regression

Commit cc216e4 ("net: sunhme: Switch SBUS to devres") changed
explicit sized of_ioremap with BMAC_REG_SIZEs to
devm_platform_ioremap_resource mapping all the resource. However,
this does not work on my Sun Ultra 2 with SBUS HMEs:

hme f0072f38: error -EBUSY: can't request region for resource [mem 0x1ffe8c07000-0x1ffe8c0701f]
hme f0072f38: Cannot map TCVR registers.
hme f0072f38: probe with driver hme failed with error -16
hme f007ab44: error -EBUSY: can't request region for resource [mem 0x1ff28c07000-0x1ff28c0701f]
hme f007ab44: Cannot map TCVR registers.
hme f007ab44: probe with driver hme failed with error -16

Turns out the open-firmware resources overlap, at least on this
machines and PROM version:

hexdump /proc/device-tree/sbus@1f,0/SUNW,hme@2,8c00000/reg:
00 00 00 02 08 c0 00 00  00 00 01 08
00 00 00 02 08 c0 20 00  00 00 20 00
00 00 00 02 08 c0 40 00  00 00 20 00
00 00 00 02 08 c0 60 00  00 00 20 00
00 00 00 02 08 c0 70 00  00 00 00 20

And the driver previously explicitly mapped way smaller mmio regions:

/proc/iomem:
1ff28c00000-1ff28c00107 : HME Global Regs
1ff28c02000-1ff28c02033 : HME TX Regs
1ff28c04000-1ff28c0401f : HME RX Regs
1ff28c06000-1ff28c0635f : HME BIGMAC Regs
1ff28c07000-1ff28c0701f : HME Tranceiver Regs

Quirk this specific issue by truncating the previous resource to not
overlap into the TCVR registers.

Fixes: cc216e4 ("net: sunhme: Switch SBUS to devres")
Signed-off-by: René Rebe <rene@exactco.de>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
Link: https://patch.msgid.link/20260205.170959.89574674688839340.rene@exactco.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: rxrbln

drivers/net/ethernet/sun/sunhme.c

@@ -2551,6 +2551,9 @@ static int happy_meal_sbus_probe_one(struct platform_device *op, int is_qfe)
 		goto err_out_clear_quattro;
 	}
 
+	/* BIGMAC may have bogus sizes */
+	if ((op->resource[3].end - op->resource[3].start) >= BMAC_REG_SIZE)
+		op->resource[3].end = op->resource[3].start + BMAC_REG_SIZE - 1;
 	hp->bigmacregs = devm_platform_ioremap_resource(op, 3);
 	if (IS_ERR(hp->bigmacregs)) {
 		dev_err(&op->dev, "Cannot map BIGMAC registers.\n");