[sh4] code translation bug fix

[sh4] code translation bug fix

When a TLB miss occurs while pre-decrement store instruction such as
"mov.l Rm, @-Rn" is executed, re-execution of such instruction cause
status confusion. Because pre Rn decrement is executed before TLB miss,
re-execution decrements Rn again.
In other words, in a translated instruction array, register status
should not modified before memory access instruction.

(Shin-ichiro KAWASAKI)

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5069 c046a42c-6fe2-441c-8c8c-71466251a162