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>

board/prodrive/pdnb3/pdnb3.c

@@ -29,7 +29,6 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 /* Prototypes */
-int gunzip(void *, int, unsigned char *, unsigned long *);
 int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
 
 /* predefine these here for FPGA programming (before including fpga.c) */