linux-user: Remove a.out declarations from elfload.c

These should have been removed with the rest of the stub a.out
support in b9329d4b5321, though they were not in use even then.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/elfload.c

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 12d4873..26c090c 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -178,25 +178,6 @@
 
 #include "elf.h"
 
-struct exec
-{
-    unsigned int a_info;   /* Use macros N_MAGIC, etc for access */
-    unsigned int a_text;   /* length of text, in bytes */
-    unsigned int a_data;   /* length of data, in bytes */
-    unsigned int a_bss;    /* length of uninitialized data area, in bytes */
-    unsigned int a_syms;   /* length of symbol table data in file, in bytes */
-    unsigned int a_entry;  /* start address */
-    unsigned int a_trsize; /* length of relocation info for text, in bytes */
-    unsigned int a_drsize; /* length of relocation info for data, in bytes */
-};
-
-
-#define N_MAGIC(exec) ((exec).a_info & 0xffff)
-#define OMAGIC 0407
-#define NMAGIC 0410
-#define ZMAGIC 0413
-#define QMAGIC 0314
-
 #define DLINFO_ITEMS 16
 
 static inline void memcpy_fromfs(void * to, const void * from, unsigned long n)