xen/arm32: Tidy up setup_mm()

The current look and feel of setup_mm() leaves a lot to be desired. The
scope of variables is not the best, many variables are not really needed
while some others are set but not used. The first iteration of membanks
is split from the loop for no reason. Tidy up this function for better
readability.

No functional change.

Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Hari Limaye <hari.limaye@arm.com>
Tested-by: Hari Limaye <hari.limaye@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/arch/arm/arm32/mmu/mm.c

@@ -74,8 +74,7 @@ static paddr_t __init fit_xenheap_in_static_heap(uint32_t size, paddr_t align)
 void __init setup_mm(void)
 {
     const struct membanks *mem = bootinfo_get_mem();
-    paddr_t ram_start, ram_end, ram_size, e, bank_start, bank_end, bank_size;
-    paddr_t static_heap_end = 0, static_heap_size = 0;
+    paddr_t ram_start = INVALID_PADDR, ram_end = 0, ram_size = 0, e;
     unsigned long heap_pages, xenheap_pages, domheap_pages;
     unsigned int i;
     const uint32_t ctr = READ_CP32(CTR);
@@ -89,19 +88,14 @@ void __init setup_mm(void)
 
     init_pdx();
 
-    ram_start = mem->bank[0].start;
-    ram_size  = mem->bank[0].size;
-    ram_end   = ram_start + ram_size;
-
-    for ( i = 1; i < mem->nr_banks; i++ )
+    for ( i = 0; i < mem->nr_banks; i++ )
     {
-        bank_start = mem->bank[i].start;
-        bank_size = mem->bank[i].size;
-        bank_end = bank_start + bank_size;
+        const struct membank *bank = &mem->bank[i];
+        paddr_t bank_end = bank->start + bank->size;
 
-        ram_size  = ram_size + bank_size;
-        ram_start = min(ram_start,bank_start);
-        ram_end   = max(ram_end,bank_end);
+        ram_size = ram_size + bank->size;
+        ram_start = min(ram_start, bank->start);
+        ram_end = max(ram_end, bank_end);
     }
 
     total_pages = ram_size >> PAGE_SHIFT;
@@ -109,18 +103,14 @@ void __init setup_mm(void)
     if ( using_static_heap )
     {
         const struct membanks *reserved_mem = bootinfo_get_reserved_mem();
+        paddr_t static_heap_size = 0;
 
         for ( i = 0 ; i < reserved_mem->nr_banks; i++ )
         {
             if ( reserved_mem->bank[i].type != MEMBANK_STATIC_HEAP )
                 continue;
 
-            bank_start = reserved_mem->bank[i].start;
-            bank_size = reserved_mem->bank[i].size;
-            bank_end = bank_start + bank_size;
-
-            static_heap_size += bank_size;
-            static_heap_end = max(static_heap_end, bank_end);
+            static_heap_size += reserved_mem->bank[i].size;
         }
 
         heap_pages = static_heap_size >> PAGE_SHIFT;