[BUG] efi_check_allocated() only checks start address

AllocatePages() and FreePages() call efi_check_allocated() to check if a memory address is allocated or not.

The function should consider the number of pages in the request and either check if the full range is deallocated or the full range is allocated.

https://source.denx.de/u-boot/custodians/u-boot-efi/-/issues/7

Best regards

Heinrich