Fix powerpc 604 reset vector

According to 604eUM_book (see 8.3.3 Reset inputs p8-54), the IP bit is set
for hreset and the vector is at offset 0x100 from the exception prefix.

No difference in this area between 604 and 604e.
Signed-off-by: NTristan Gingold <gingold@adacore.com>

target-ppc/translate_init.c

@@ -2875,9 +2875,9 @@ static void init_excp_604 (CPUPPCState *env)
     env->excp_vectors[POWERPC_EXCP_PERFM]    = 0x00000F00;
     env->excp_vectors[POWERPC_EXCP_IABR]     = 0x00001300;
     env->excp_vectors[POWERPC_EXCP_SMI]      = 0x00001400;
-    env->hreset_excp_prefix = 0x00000000UL;
+    env->hreset_excp_prefix = 0xFFF00000UL;
     /* Hardware reset vector */
-    env->hreset_vector = 0xFFFFFFFCUL;
+    env->hreset_vector = 0x00000100UL;
 #endif
 }