platform/x86: mlx-platform: Add define for the negative bus

Add define for the negative bus ID in order to use it in case no hotplug
device is associated with the hotplug interrupt signal. In this case,
the signal will be handled by the mlxreg-hotplug driver, but no device
will be associated with the signal.
Signed-off-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/mlx-platform.c

@@ -90,6 +90,7 @@
 #define MLXPLAT_CPLD_LPC_MUX_DEVS		2
 
 /* Hotplug devices adapter numbers */
+#define MLXPLAT_CPLD_NR_NONE			-1
 #define MLXPLAT_CPLD_PSU_DEFAULT_NR		10
 #define MLXPLAT_CPLD_FAN1_DEFAULT_NR		11
 #define MLXPLAT_CPLD_FAN2_DEFAULT_NR		12