target/sh4: sync fp_status when gdb writes FPSCR

sh4_cpu_gdb_write_register() wrote the incoming FPSCR value straight into env->fpscr, leaving the derived env->fp_status (rounding mode and flush-to-zero) stale, so a gdb-initiated FPSCR change did not take effect for subsequent FP operations. Use cpu_load_fpscr() instead, the same way the adjacent case already uses cpu_write_sr() for SR. Cc: qemu-stable@nongnu.org Reviewed-by: Yoshinori Sato <yoshinori.sato@nifty.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Matt Turner <mattst88@gmail.com> Signed-off-by: Helge Deller <deller@gmx.de>