device: adjust NM_L3CFG_CONFIG_PRIORITY_IPV6LL and L3_CONFIG_DATA_TYPE_LL_6

NM_L3CFG_CONFIG_PRIORITY_IPV6LL and L3_CONFIG_DATA_TYPE_LL_6 are
somewhat related. They probably should be numerically identical.

Now, L3_CONFIG_DATA_TYPE_LL_6 cannot be zero (because
L3_CONFIG_DATA_TYPE_LL_4 is zero and L3ConfigDataType values must be
distinct). Therefore, also bump NM_L3CFG_CONFIG_PRIORITY_IPV6LL to 1.
Of course, NM_L3CFG_CONFIG_PRIORITY_IPV6LL is not obviously more important
than NM_L3CFG_CONFIG_PRIORITY_IPV4LL. But to be consistent with
L3_CONFIG_DATA_TYPE_LL_6 is probably more important here.

src/core/devices/nm-device.c

@@ -190,6 +190,7 @@ typedef enum {
 } L3ConfigDataType;
 
 G_STATIC_ASSERT(NM_L3CFG_CONFIG_PRIORITY_IPV4LL == L3_CONFIG_DATA_TYPE_LL_4);
+G_STATIC_ASSERT(NM_L3CFG_CONFIG_PRIORITY_IPV6LL == L3_CONFIG_DATA_TYPE_LL_6);
 
 typedef enum {
     HW_ADDR_TYPE_UNSET = 0,

src/core/nm-l3cfg.h

@@ -7,7 +7,7 @@
 #include "nm-l3-config-data.h"
 
 #define NM_L3CFG_CONFIG_PRIORITY_IPV4LL 0
-#define NM_L3CFG_CONFIG_PRIORITY_IPV6LL 0
+#define NM_L3CFG_CONFIG_PRIORITY_IPV6LL 1
 #define NM_ACD_TIMEOUT_RFC5227_MSEC     9000u
 
 #define NM_TYPE_L3CFG            (nm_l3cfg_get_type())