add .clang-format

In our environment, clang-format runs with '-style=file'. With
this parameter, clang-format searches recursively to the top
of the tree, looking for a file called .clang-format. clang-format
adopts the formatting style specified by the first matching
file.

Add .clang-format, to specify that wifilogd code should use
Google formatting style.

Bug: 32781722
Test: None
Change-Id: Ibf68c592544470e4df10e89843d1ff663f4f2c03
1 file changed