move prototypes for gunzip() and zunzip() to common.h

Prototype for gunzip/zunzip was only in lib_generic/gunzip.c and thus
repeated in every file using it. This patch moves the prototypes to
common.h and removes all prototypes distributed anywhere else.

Signed-off-by: Wolfgang Wegner <w.wegner@astro-kom.de>
diff --git a/include/common.h b/include/common.h
index 00b5434..07897f6 100644
--- a/include/common.h
+++ b/include/common.h
@@ -612,6 +612,11 @@
 ulong	ticks2usec    (unsigned long ticks);
 int	init_timebase (void);
 
+/* lib_generic/gunzip.c */
+int gunzip(void *, int, unsigned char *, unsigned long *);
+int zunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp,
+						int stoponerr, int offset);
+
 /* lib_generic/time.c */
 void	udelay        (unsigned long);