[U-Boot] efi_loader: Fix crash on 32-bit systems

[Alexander Graf]

> A type mismatch in the efi_allocate_pool boot service flow causes
> hazardous memory scribbling on 32-bit systems.
> 
> This is efi_allocate_pool's prototype:
> 
> static efi_status_t EFIAPI efi_allocate_pool(int pool_type,
> 						    unsigned long size,
> 						    void **buffer);
> 
> Internally, it invokes efi_allocate_pages as follows:
> 
> efi_allocate_pages(0, pool_type, (size + 0xfff) >> 12,
> 					    (void*)buffer);
> 
> This is efi_allocate_pages' prototype:
> 
> efi_status_t efi_allocate_pages(int type, int memory_type,
> 					unsigned long pages,
> 					uint64_t *memory);
> 
> The problem: efi_allocate_pages does this internally:
> 
>     *memory = addr;
> 
> This fix in efi_allocate_pool uses a transitional uintptr_t cast to
> ensure the correct outcome, irrespective of the system's native word
> size.
> 
> This was observed when bootefi'ing the EFI instance of FreeBSD's first
> stage bootstrap (boot1.efi) on a 32-bit ARM platform (Qemu VExpress +
> Cortex-a9).
> 
> Signed-off-by: Robin Randhawa <robin.randhawa at arm.com>

Thanks, applied to