target-mips: fix user-mode emulation startup

target-mips: fix user-mode emulation startup

Running programs with the MIPS user-mode emulator fails during dynamic
loading, as floating-point instructions are not enabled in in
env->hflags.  Move the code for doing so from fpu_init to cpu_reset so
the MIPS_HFLAG_{FPU,F64} setting doesn't get clobbered by cpu_reset
setting env->hflags to MIPS_HFLAG_UM.

The same end can be achieved by swapping the ordering of fpu_init and
cpu_reset in cpu_mips_init, but it seemed better to consolidate the
CONFIG_USER_ONLY code into a single location.

Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit 91a759352623e4a3da969fa66626cc99241e9da2)