qcacld-3.0: Move SIGN_HEADER_MAGIC definition to BMI layer

FW common files needs to be in sync with host and fw.
SIGN_HEADER_MAGIC is not defined in fw common header files.
Abstract extra definition internal to host driver.

Change-Id: Ie902ca191617a6829c2cf3e6a45c3d170ae8d8c6
CRs-Fixed: 1012542

target/inc/bin_sig.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012,2014 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2012,2014, 2016 The Linux Foundation. All rights reserved.
  *
  * Previously licensed under the ISC license by Qualcomm Atheros, Inc.
  *
@@ -28,7 +28,6 @@
 #ifndef BIN_SIGN_H_
 #define BIN_SIGN_H_
 
-#define SIGN_HEADER_MAGIC 0x454D4F52
 
 /* Signed binary MetaData */
 typedef struct {