sim: fix sim-hardware configure option

The current default handling for the --enable-sim-hardware option ends up
forcing the value to whatever is set as the first argument when calling
the macro (by virtue of how autoconf works).  Relocate the setup code to
the 4th parameter of the AC_ARG_ENABLE macro to fix it.

This was caused by the simplification work in 1517bd2742.

Reported-by: Hans-Peter Nilsson <hans-peter.nilsson@axis.com>

sim/lm32/configure

@@ -13391,12 +13391,6 @@ fi
 
 
 
-if test x"yes" != x"no"; then
-  enable_sim_hardware=yes
-else
-  enable_sim_hardware=no
-fi
-
 if test ""; then
   hardware=""
 else
@@ -13411,6 +13405,8 @@ sim_hw_objs="\$(SIM_COMMON_HW_OBJS) `echo $sim_hw | sed -e 's/\([^ ][^ ]*\)/dv-\
 # Check whether --enable-sim-hardware was given.
 if test "${enable_sim_hardware+set}" = set; then :
   enableval=$enable_sim_hardware;
+else
+  enable_sim_hardware="yes"
 fi
 
 case ${enable_sim_hardware} in