target-sparc: Fix order of function parameters

target-sparc: Fix order of function parameters

The MinGW-w64 gcc complains about wrong parameters for
gen_helper_fpadd16_s and three other functions.

gen_helper_fpadd16_s is declared like this (hidden in lots of macros):

static inline void
 gen_helper_fpadd16s(TCGv_i32 retval, TCGv_ptr arg1,
                     TCGv_i32 arg2, TCGv_i32 arg3);

So it looks like cpu_env should be the 2nd parameter.

Please review this patch as I have no environment to test it
(maybe the 1st parameter should be cpu_dst?).

Cc: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>