Fix loading large process images.

2MiB large pages were being used for any large page mapping, but the
page manager doesn't correctly handle them everywhere yet. Now only
allow them for offset pointers (eg MMIO space) that will never be
unmapped.

src/kernel/page_manager.h

@@ -136,13 +136,15 @@ private:
 	/// \arg phys_addr  The starting physical address of the pages to be mapped
 	/// \arg virt_addr  The starting virtual address ot the memory to be mapped
 	/// \arg count      The number of pages to map
-	/// \art user  True if this is a userspace mapping
+	/// \arg user       True if this is a userspace mapping
+	/// \arg large      Whether to allow large pages
 	void page_in(
 			page_table *pml4,
 			uintptr_t phys_addr,
 			uintptr_t virt_addr,
 			size_t count,
-			bool user = false);
+			bool user = false,
+			bool large = false);
 
 	/// Low-level routine for unmapping a number of pages from the given page table.
 	/// \arg pml4       The root page table for this mapping