Kernel: Set Cacheable parameter to NO explicitly in DMA helpers

The cacheable parameter to allocate_kernel_region should be explicitly
set to No as this region is used to do physical memory transfers. Even
though most architectures ignore this even if it is set, it is better
to make this explicit.

Kernel/Memory/MemoryManager.cpp

@@ -748,7 +748,8 @@ ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_page(S
     dma_buffer_page = allocate_supervisor_physical_page();
     if (dma_buffer_page.is_null())
         return ENOMEM;
-    auto region_or_error = allocate_kernel_region(dma_buffer_page->paddr(), PAGE_SIZE, name, access);
+    // Do not enable Cache for this region as physical memory transfers are performed (Most architectures have this behaviour by default)
+    auto region_or_error = allocate_kernel_region(dma_buffer_page->paddr(), PAGE_SIZE, name, access, Region::Cacheable::No);
     return region_or_error;
 }
 
@@ -758,7 +759,8 @@ ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_pages(
     dma_buffer_pages = allocate_contiguous_supervisor_physical_pages(size);
     if (dma_buffer_pages.is_empty())
         return ENOMEM;
-    auto region_or_error = allocate_kernel_region(dma_buffer_pages.first().paddr(), size, name, access);
+    // Do not enable Cache for this region as physical memory transfers are performed (Most architectures have this behaviour by default)
+    auto region_or_error = allocate_kernel_region(dma_buffer_pages.first().paddr(), size, name, access, Region::Cacheable::No);
     return region_or_error;
 }