Kernel: Use Userspace<T> for the sethostname syscall

Author: https://github.com/bgianfo
Commit: cfedd62b5c
Pull-request: https://github.com/SerenityOS/serenity/pull/3062
Reviewed-by: https://github.com/awesomekling

Kernel/Process.h

@@ -251,7 +251,7 @@ public:
     int sys$clock_settime(clockid_t, Userspace<const timespec*>);
     int sys$clock_nanosleep(Userspace<const Syscall::SC_clock_nanosleep_params*>);
     int sys$gethostname(Userspace<char*>, ssize_t);
-    int sys$sethostname(const char*, ssize_t);
+    int sys$sethostname(Userspace<const char*>, ssize_t);
     int sys$uname(utsname*);
     int sys$readlink(Userspace<const Syscall::SC_readlink_params*>);
     int sys$ttyname(int fd, Userspace<char*>, size_t);