efi_loader: Simplify efi_free_pages()

We currently call efi_free_pages() with a notify flag and explicitly
update the efi memory map. That's not needed as lmb_free_flags() will do
that for us if the LMB_NONOTIFY flag is removed

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index 9f3f087..d2f5d56 100644
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -521,7 +521,6 @@
 efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages)
 {
 	u64 len;
-	uint flags;
 	long status;
 	efi_status_t ret;
 
@@ -536,18 +535,17 @@
 		return EFI_INVALID_PARAMETER;
 	}
 
-	flags = LMB_NOOVERWRITE | LMB_NONOTIFY;
 	len = (u64)pages << EFI_PAGE_SHIFT;
+	/*
+	 * The 'memory' variable for sandbox holds a pointer which has already
+	 * been mapped with map_sysmem() from efi_allocate_pages(). Convert
+	 * it back to an address LMB understands
+	 */
 	status = lmb_free_flags(map_to_sysmem((void *)(uintptr_t)memory), len,
-				flags);
+				LMB_NOOVERWRITE);
 	if (status)
 		return EFI_NOT_FOUND;
 
-	ret = efi_add_memory_map_pg(memory, pages, EFI_CONVENTIONAL_MEMORY,
-				    false);
-	if (ret != EFI_SUCCESS)
-		return EFI_NOT_FOUND;
-
 	return ret;
 }