arm64/efi: set EFI_ALLOC_ALIGN to 64 KB

Set EFI_ALLOC_ALIGN to 64 KB so that all allocations done by the stub
are naturally compatible with a 64 KB granule kernel.
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

arch/arm64/include/asm/efi.h

@@ -44,4 +44,6 @@ extern void efi_idmap_init(void);
 
 #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__)
 
+#define EFI_ALLOC_ALIGN		SZ_64K
+
 #endif /* _ASM_EFI_H */