mips32, dsp563xx: fix segfault on Gdb attach

Since c6216201b2 gdb target description
generation support is enabled by default and it counts on checking
"feature" pointer in reg_list. Both mips32 and dsp563xx neither used
calloc nor explicitly set feature (as it was a newly introduced struct
field).

This patch changes all targets to use calloc for consistency.

Change-Id: I9eceadef8b04aacb108e24ae23cb51ca3009586f
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2102
Tested-by: jenkins
Reviewed-by: Salvador Arroyo <sarroyofdez@yahoo.es>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

src/target/mips32.c

@@ -252,7 +252,7 @@ struct reg_cache *mips32_build_reg_cache(struct target *target)
 	int num_regs = MIPS32NUMCOREREGS;
 	struct reg_cache **cache_p = register_get_last_cache_p(&target->reg_cache);
 	struct reg_cache *cache = malloc(sizeof(struct reg_cache));
-	struct reg *reg_list = malloc(sizeof(struct reg) * num_regs);
+	struct reg *reg_list = calloc(num_regs, sizeof(struct reg));
 	struct mips32_core_reg *arch_info = malloc(sizeof(struct mips32_core_reg) * num_regs);
 	int i;