Add init_priority to generated code

Fix a issue(crash) on `FEATURE_SENSORS_CACHE` is enabled.
As below backtrace:
```
...
4  0x75ff9a34 in initSensorMatches () at ../../../../../../workspace/sources/phosphor-ipmi-host/sensorhandler.cpp:153
5  0x75f887a8 in register_netfn_sen_functions () at ../../../../../../workspace/sources/phosphor-ipmi-host/sensorhandler.cpp:1561
...
```

This issue is caused by `ipmi::sensor::sensors` is not initialized when
register_netfn_sen_functions is called.
Add init_priority to generated code to fix this issue.

Tested: Build okay and no crash.

Signed-off-by: Jian Zhang <zhangjian.3032@bytedance.com>
Change-Id: Ic5cc96206f3df9fafa10bbfb88c0bb4459749575
diff --git a/scripts/readfru.mako.cpp b/scripts/readfru.mako.cpp
index 57265be..e7fbab8 100644
--- a/scripts/readfru.mako.cpp
+++ b/scripts/readfru.mako.cpp
@@ -2,7 +2,7 @@
 #include <iostream>
 #include "fruread.hpp"
 
-extern const FruMap frus = {
+extern const FruMap __attribute__((init_priority(101))) frus = {
 % for key in fruDict.keys():
    {${key},{
 <%