i2c: i801: Annotate apanel_addr as __ro_after_init

Annotate this variable as __ro_after_init to protect it from being
overwritten later.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

Author: hkallweit

drivers/i2c/busses/i2c-i801.c

@@ -1060,7 +1060,7 @@ static const struct pci_device_id i801_ids[] = {
 MODULE_DEVICE_TABLE(pci, i801_ids);
 
 #if defined CONFIG_X86 && defined CONFIG_DMI
-static unsigned char apanel_addr;
+static unsigned char apanel_addr __ro_after_init;
 
 /* Scan the system ROM for the signature "FJKEYINF" */
 static __init const void __iomem *bios_signature(const void __iomem *bios)