Please update addaddmul_1msb0.asm to support ABI in mingw64

[Idigger Lee]

 hi,

Please update addaddmul_1msb0.asm to support ABI in mingw64.


mpn/x86_64/addaddmul_1msb0.asm

//------

ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)

ASM_START()
    TEXT
    ALIGN(16)
PROLOGUE(mpn_addaddmul_1msb0)
    FUNC_ENTRY(4)
IFDOS(`    mov    56(%rsp), %r8    ')
IFDOS(`    mov    64(%rsp), %r9    ')

//  ......

    FUNC_EXIT()
    ret

//---

Thanks a lot.