Fix Python API CMake file ETHOS_U_DRIVER_LIB path

The ETHOS_U_DRIVER_LIB environment variable in the Python API CMake file
specifies that the driver library archive will be found in a lib
subdirectory in the build directory. This is incorrect as the archive
will be put directly into the driver library directory and the CMake
file has been updated accordingly.

Change-Id: Ie296f89f7669d69f193d96d994ad8e1918e3d1eb
diff --git a/driver_library/python/CMakeLists.txt b/driver_library/python/CMakeLists.txt
index 6554730..a16c612 100644
--- a/driver_library/python/CMakeLists.txt
+++ b/driver_library/python/CMakeLists.txt
@@ -33,7 +33,7 @@
 # local env variables passed down to the python scripts
 # scripts can thus be used standalone
 set(DRIVER_ENV ETHOS_U_DRIVER_INCLUDE="${PROJECT_SOURCE_DIR}/include"
-               ETHOS_U_DRIVER_LIB=${PROJECT_BINARY_DIR}/lib)
+               ETHOS_U_DRIVER_LIB="${PROJECT_BINARY_DIR}")
 
 # common step - generates swig wrappers
 add_custom_command(OUTPUT ${OUT_WRAP}