AP_Baro: To prevent incorrect warnings

[muramura]

BUF is a stack variable.
It is not used after being released. Suppress the compiler warning.

[ 84/1342] Compiling libraries/AP_Baro/AP_Baro_BMP388.cpp
../../libraries/AP_Baro/AP_Baro_BMP388.cpp: In member function ‘void AP_Baro_BMP388::timer()’:
../../libraries/AP_Baro/AP_Baro_BMP388.cpp:148:34: warning: dangling pointer to ‘buf’ may be used [-Wdangling-pointer=]
148 | update_temperature((buf[6] << 16) | (buf[5] << 8) | buf[4]);
| ~~~~~^
../../libraries/AP_Baro/AP_Baro_BMP388.cpp:136:13: note: ‘buf’ declared here
136 | uint8_t buf[7];
| ^~~

[peterbarker]

LGTM

[peterbarker]

Ah. We're going to have to limit this to specific versions of compilers - not understood on older GCCs, for example