riscv64: partially revert cb9d1f53717dd67892ba943626f3d1b46f3e760b, fixes no MMU ELF

libc/sysdeps/linux/riscv64/crt1.S

@@ -45,9 +45,6 @@
 	.globl	_start
 	.type	_start,%function
 
-	.weak _init
-	.weak _fini
-
 _start:
 	call  .Lload_gp
 	mv    a5, a0  /* rtld_fini.  */
@@ -55,9 +52,9 @@ _start:
 	la   a0, main
 	REG_L a1, 0(sp)      /* argc.  */
 	addi  a2, sp, SZREG  /* argv.  */
+	mv    a3, zero
+	mv    a4, zero
 	andi  sp, sp, ALMASK /* Align stack. */
-	lla   a3, _init
-	lla   a4, _fini
 	mv    a6, sp  /* stack_end.  */
 
 	tail  __uClibc_main@plt