make munmap free physical pages, and one correction for aligned mmap in syscall.c (extend_process_region is called with memory-region start-address which is aligned (map_end_aligned), instead of tail-address of current-region (region->map_end)) for aligned mmap (in syscall.c)

kernel/mem.c

@@ -40,6 +40,12 @@ void *allocate_pages(int npages, enum aal_mc_ap_flag flag)
 	return pa ? phys_to_virt(pa) : 0; 
 }
 
+void free_pages_pa(unsigned long pa, int npages)
+{
+    kprintf("mem.c,free_pages_pa,pa=%lx\n", pa);
+	aal_pagealloc_free(pa_allocator, pa, npages);
+}
+
 void free_pages(void *va, int npages)
 {
 	aal_pagealloc_free(pa_allocator, virt_to_phys(va), npages);