cpu-exec: remove unnecessary assignment

Avoid this warning from clang analyzer:
/src/qemu/cpu-exec.c:97:5: warning: Value stored to 'phys_page2' is never read
    phys_page2 = -1;

Adjust the scope of the variable while at it.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

cpu-exec.c

@@ -86,7 +86,7 @@ static TranslationBlock *tb_find_slow(CPUState *env,
 {
     TranslationBlock *tb, **ptb1;
     unsigned int h;
-    tb_page_addr_t phys_pc, phys_page1, phys_page2;
+    tb_page_addr_t phys_pc, phys_page1;
     target_ulong virt_page2;
 
     tb_invalidated_flag = 0;
@@ -94,7 +94,6 @@ static TranslationBlock *tb_find_slow(CPUState *env,
     /* find translated block using physical mappings */
     phys_pc = get_page_addr_code(env, pc);
     phys_page1 = phys_pc & TARGET_PAGE_MASK;
-    phys_page2 = -1;
     h = tb_phys_hash_func(phys_pc);
     ptb1 = &tb_phys_hash[h];
     for(;;) {
@@ -107,6 +106,8 @@ static TranslationBlock *tb_find_slow(CPUState *env,
             tb->flags == flags) {
             /* check next page if needed */
             if (tb->page_addr[1] != -1) {
+                tb_page_addr_t phys_page2;
+
                 virt_page2 = (pc & TARGET_PAGE_MASK) +
                     TARGET_PAGE_SIZE;
                 phys_page2 = get_page_addr_code(env, virt_page2);