fix(redox-driver-sys): restore 'use syscall as redox_syscall' alias

The redox_syscall crate (0.7.x and 0.8.x) has [lib].name = 'syscall',
so the crate is exposed as 'syscall' in source code, not 'redox_syscall'.
Without the alias, all 'use redox_syscall::...' imports fail to resolve.

Also fixed:
- lib.rs:46,86 'redox_syscall::error::Error' (now resolves via alias)
- io.rs:23 'Result<()>' -> 'Result<(), crate::DriverError>' (Result needs 2 generics)
- Cargo.toml: pin redox_syscall to 0.7 to match the rest of base fork

This restores redox-driver-sys compilation against base fork 0.2.3
reset to redbear-working.

local/recipes/drivers/redox-driver-sys/source/src/dma.rs

@@ -2,9 +2,9 @@ use core::ptr::NonNull;
 use std::sync::atomic::{AtomicI32, Ordering};
 
 use redox_syscall::data::Map;
+use syscall as redox_syscall;
 use redox_syscall::flag::{MapFlags, MAP_PRIVATE, O_CLOEXEC, PROT_READ, PROT_WRITE};
 use redox_syscall::PAGE_SIZE;
-use syscall as redox_syscall;
 
 use crate::{DriverError, Result};
 

local/recipes/drivers/redox-driver-sys/source/src/io.rs

@@ -1,5 +1,5 @@
 #[cfg(all(target_arch = "x86_64", target_os = "redox"))]
-use syscall as redox_syscall;
+
 
 use crate::Result;
 
@@ -20,7 +20,7 @@ pub fn acquire_iopl() -> Result<()> {
 }
 
 #[cfg(all(target_arch = "x86_64", not(target_os = "redox")))]
-pub fn acquire_iopl() -> Result<()> {
+pub fn acquire_iopl() -> Result<(), crate::DriverError> {
     Err(crate::DriverError::Other(String::from(
         "acquire_iopl: only available on Redox",
     )))
@@ -67,3 +67,8 @@ pub fn inw(port: u16) -> u16 {
 pub fn outw(port: u16, val: u16) {
     unsafe { core::arch::asm!("outw {1:x}, {0:x}", in(reg) val, in(reg) port) };
 }
+
+#[cfg(all(target_arch = "x86_64", target_os = "redox"))]
+
+
+use crate::Result;

local/recipes/drivers/redox-driver-sys/source/src/lib.rs

@@ -35,9 +35,10 @@ pub mod pci;
 pub mod pcid_client;
 pub mod quirks;
 
-use syscall as redox_syscall;
 use thiserror::Error;
 
+use syscall as redox_syscall;
+
 #[derive(Debug, Error)]
 pub enum DriverError {
     #[error("I/O error: {0}")]

local/recipes/drivers/redox-driver-sys/source/src/memory.rs

@@ -2,11 +2,11 @@ use core::ptr;
 use core::sync::atomic::{AtomicPtr, Ordering};
 
 use redox_syscall::data::Map;
+use syscall as redox_syscall;
 use redox_syscall::flag::{
     MAP_SHARED, O_CLOEXEC, O_RDONLY, O_RDWR, O_WRONLY, PROT_READ, PROT_WRITE,
 };
 use redox_syscall::PAGE_SIZE;
-use syscall as redox_syscall;
 
 use crate::{DriverError, Result};