loader: pass args along to unix in C
There's no reason why we can't pass the args gotten from the bootloader to
unix in C.
Note: loader's _start sets the ATAG pointer to 0x100.  This change simply
propagates it to unix.

*** 9,18 ****
--- 9,19 ----
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
   * Copyright (c) 2013 Joyent, Inc.  All rights reserved.
+  * Copyright (c) 2015 Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
   */
  
  #ifndef _FAKELOADER_H
  #define _FAKELOADER_H
  
*** 51,61 ****
   * ASM operations
   */
  extern void fakeload_unaligned_enable(void);
  extern void fakeload_mmu_enable(void);
  extern void fakeload_pt_setup(uintptr_t);
! extern void fakeload_exec(uintptr_t);
  
  extern void armv6_dcache_disable(void);
  extern void armv6_dcache_enable(void);
  extern void armv6_dcache_inval(void);
  extern void armv6_dcache_flush(void);
--- 52,62 ----
   * ASM operations
   */
  extern void fakeload_unaligned_enable(void);
  extern void fakeload_mmu_enable(void);
  extern void fakeload_pt_setup(uintptr_t);
! extern void fakeload_exec(void *, void *, atag_header_t *, uintptr_t);
  
  extern void armv6_dcache_disable(void);
  extern void armv6_dcache_enable(void);
  extern void armv6_dcache_inval(void);
  extern void armv6_dcache_flush(void);