Fixed file description and applied doxygen style

Removed old style file description and documnetation and apply
doxygen synatx.

Change-Id: I3ac9f06d4f574bf3c79c6f6044cec3a7e2f6e4c8
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/drivers/interrupt_controller/system_apic.c b/drivers/interrupt_controller/system_apic.c
index 37ab497..ab36927 100644
--- a/drivers/interrupt_controller/system_apic.c
+++ b/drivers/interrupt_controller/system_apic.c
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-/*
+/**
  * @file
  * @brief  system module for variants with LOAPIC
  *