x86emu: re-align breaks in ins() and outs()

Makes the 4-byte cases match those for 1- & 2-byte handling, moving the break from being unconditionally hit the first time through the to loop to after the loop is done.

Fixes Solaris Studio compiler warnings:

"prim_ops.c", line 2626: warning: end-of-loop code not reached
"prim_ops.c", line 2692: warning: end-of-loop code not reached

I found this when resyncing a copy of the x86emu code in Solaris that is used in our vbiosd for configuring a text console on the graphics output with the latest Xorg sources. I have no test case for this, but it looks correct and matches the other cases, and it's been in use in our vbiosd since 2019.