clang updates

The openbmc CI was recently updated to clang-12 which requires some
formatting updates to the code:
https://github.com/openbmc/openbmc-build-scripts/commit/4569bf49daaebff06be0482426908bb5497fad08

Make those updates and refresh the clang-format file with the one from
docs:
https://github.com/openbmc/docs/blob/master/style/cpp/.clang-format

Change-Id: Ieb3626526373a053ec84431e7560003f229f338d
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/gpio.hpp b/gpio.hpp
index 0969995..a803113 100644
--- a/gpio.hpp
+++ b/gpio.hpp
@@ -12,8 +12,8 @@
 namespace gpio
 {
 
-typedef std::remove_reference<decltype(
-    gpiohandle_request::lineoffsets[0])>::type gpioNum_t;
+typedef std::remove_reference<
+    decltype(gpiohandle_request::lineoffsets[0])>::type gpioNum_t;
 
 typedef std::remove_reference<decltype(gpiohandle_data::values[0])>::type
     gpioValue_t;
@@ -62,8 +62,7 @@
      */
     GPIO(const std::string& device, gpioNum_t gpio, Direction direction) :
         device(device), gpio(gpio), direction(direction)
-    {
-    }
+    {}
 
     /**
      * Reads the GPIO value