target-xtensa: make default CPU depend on target endianness

This makes usable default for -cpu option both for qemu-system-xtensa
and qemu-system-xtensaeb fixing the following error:

    $ qemu-system-xtensaeb -M sim
    Unable to find CPU definition
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Tested-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

hw/xtensa_lx60.c

@@ -173,7 +173,7 @@ static void lx_init(const LxBoardDesc *board,
     int n;
 
     if (!cpu_model) {
-        cpu_model = "dc232b";
+        cpu_model = XTENSA_DEFAULT_CPU_MODEL;
     }
 
     for (n = 0; n < smp_cpus; n++) {
@@ -300,14 +300,14 @@ static void xtensa_lx200_init(ram_addr_t ram_size,
 
 static QEMUMachine xtensa_lx60_machine = {
     .name = "lx60",
-    .desc = "lx60 EVB (dc232b)",
+    .desc = "lx60 EVB (" XTENSA_DEFAULT_CPU_MODEL ")",
     .init = xtensa_lx60_init,
     .max_cpus = 4,
 };
 
 static QEMUMachine xtensa_lx200_machine = {
     .name = "lx200",
-    .desc = "lx200 EVB (dc232b)",
+    .desc = "lx200 EVB (" XTENSA_DEFAULT_CPU_MODEL ")",
     .init = xtensa_lx200_init,
     .max_cpus = 4,
 };

hw/xtensa_sim.c

@@ -102,7 +102,7 @@ static void xtensa_sim_init(ram_addr_t ram_size,
                      const char *initrd_filename, const char *cpu_model)
 {
     if (!cpu_model) {
-        cpu_model = "dc232b";
+        cpu_model = XTENSA_DEFAULT_CPU_MODEL;
     }
     sim_init(ram_size, boot_device, kernel_filename, kernel_cmdline,
             initrd_filename, cpu_model);
@@ -110,7 +110,7 @@ static void xtensa_sim_init(ram_addr_t ram_size,
 
 static QEMUMachine xtensa_sim_machine = {
     .name = "sim",
-    .desc = "sim machine (dc232b)",
+    .desc = "sim machine (" XTENSA_DEFAULT_CPU_MODEL ")",
     .init = xtensa_sim_init,
     .max_cpus = 4,
 };

target-xtensa/cpu.h

@@ -351,6 +351,12 @@ typedef struct CPUXtensaState {
 #define cpu_signal_handler cpu_xtensa_signal_handler
 #define cpu_list xtensa_cpu_list
 
+#ifdef TARGET_WORDS_BIGENDIAN
+#define XTENSA_DEFAULT_CPU_MODEL "fsf"
+#else
+#define XTENSA_DEFAULT_CPU_MODEL "dc232b"
+#endif
+
 XtensaCPU *cpu_xtensa_init(const char *cpu_model);
 
 static inline CPUXtensaState *cpu_init(const char *cpu_model)