d2-common/gps: Fix build with gcc 4.8

from qcom/gps-
log_util.h uses constructs that gcc 4.8 warns about because they
can be interpreted as C++11 string literals.
Since qcom/gps is built with -Werror, this causes the build to fail.

Change-Id: I0b9fab01a4b1d7b269e33ba3d6014da917422b7d
Signed-off-by: Bernhard Rosenkränzer <Bernhard.Rosenkranzer@linaro.org>