ext hal qmsi: Avoid QMSI specific flags when QMSI is not used

The way the build system works, the Makefiles under ext/hal/* are being
included unconditionally, so anything they add to the build flags needs
to be protected by the correct configuration value.

Change-Id: I238e04cd836dd9e4c5d83040822039c68abb6b17
Signed-off-by: Iván Briano <ivan.briano@intel.com>