efi_loader: Fix loaded image alignment

We are ignoring the alignment communicated via the PE/COFF header.
Starting 5.10 the Linux kernel will loudly complain about it. For more
details look at [1] (in linux kernel).

So add a function that can allocate aligned EFI memory and use it for our
relocated loaded image.

[1] c32ac11da3f83 ("efi/libstub: arm64: Double check image alignment at entry")

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Vincent Stehlé <vincent.stehle@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/include/efi_loader.h b/include/efi_loader.h
index c440962..5cdc723 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -675,6 +675,8 @@
 #define efi_size_in_pages(size) (((size) + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
 /* Generic EFI memory allocator, call this to get memory */
 void *efi_alloc(uint64_t len, int memory_type);
+/* Allocate pages on the specified alignment */
+void *efi_alloc_aligned_pages(u64 len, int memory_type, size_t align);
 /* More specific EFI memory allocator, called by EFI payloads */
 efi_status_t efi_allocate_pages(enum efi_allocate_type type,
 				enum efi_memory_type memory_type,