[bwn] add Q52 macros.

The PHY-N code uses a different format for gain values, so these macros
are used for converting to/from and print out values.

sys/dev/bwn/if_bwn_util.h

@@ -55,6 +55,12 @@ bwn_clamp_val(int val, int lo, int hi)
 	return val;
 }
 
+/* Q52 format - used in PHY routines */
+#define	INT_TO_Q52(i)		((i) << 2)
+#define	Q52_TO_INT(q52)		((q52) >> 2)
+#define	Q52_FMT			"%u.%u"
+#define	Q52_ARG(q52)		Q52_TO_INT(q52), ((((q52) & 0x3) * 100) / 4)
+
 extern	unsigned int bwn_sqrt(struct bwn_mac *mac, unsigned int x);
 
 #endif	/* __IF_BWN_UTIL_H__ */