nvme_drv: reject requests with unaligned offset

Since the driver relies on all requests being Nvme::MPS_LOG2 aligned
as advertised in its Block::Info the added check will reject any
misaligned requests (using 'gpt_write' led to an IOMMU write fault).

Issue #4486.

repos/os/src/drivers/nvme/main.cc

@@ -1649,6 +1649,9 @@ class Nvme::Driver : Genode::Noncopyable
 				return Response::RETRY;
 			}
 
+			if (!Genode::aligned(request.offset, Nvme::MPS_LOG2))
+				return Response::REJECTED;
+
 			switch (request.operation.type) {
 			case Block::Operation::Type::INVALID:
 				return Response::REJECTED;