Kernel: Remove read_tsc() syscall

Since nothing is using this, let's just remove it. That's one less
thing to worry about.

Kernel/Process.cpp

@@ -2515,18 +2515,6 @@ int Process::sys$rmdir(const char* pathname)
     return VFS::the().rmdir(StringView(pathname), current_directory());
 }
 
-int Process::sys$read_tsc(u32* lsw, u32* msw)
-{
-    if (!validate_write_typed(lsw))
-        return -EFAULT;
-    if (!validate_write_typed(msw))
-        return -EFAULT;
-    read_tsc(*lsw, *msw);
-    if (!is_superuser())
-        *lsw &= ~0xfff;
-    return 0;
-}
-
 int Process::sys$chmod(const char* pathname, mode_t mode)
 {
     if (!validate_read_str(pathname))

Kernel/Process.h

@@ -184,7 +184,6 @@ public:
     int sys$rmdir(const char* pathname);
     int sys$mount(const char* device, const char* mountpoint, const char* fstype);
     int sys$umount(const char* mountpoint);
-    int sys$read_tsc(u32* lsw, u32* msw);
     int sys$chmod(const char* pathname, mode_t);
     int sys$fchmod(int fd, mode_t);
     int sys$chown(const char* pathname, uid_t, gid_t);

Kernel/Syscall.h

@@ -79,7 +79,7 @@ typedef u32 socklen_t;
     __ENUMERATE_SYSCALL(select)                     \
     __ENUMERATE_SYSCALL(unlink)                     \
     __ENUMERATE_SYSCALL(poll)                       \
-    __ENUMERATE_SYSCALL(read_tsc)                   \
+    __ENUMERATE_REMOVED_SYSCALL(read_tsc)           \
     __ENUMERATE_SYSCALL(rmdir)                      \
     __ENUMERATE_SYSCALL(chmod)                      \
     __ENUMERATE_SYSCALL(usleep)                     \

Libraries/LibC/unistd.cpp

@@ -439,12 +439,6 @@ void sync()
     syscall(SC_sync);
 }
 
-int read_tsc(unsigned* lsw, unsigned* msw)
-{
-    int rc = syscall(SC_read_tsc, lsw, msw);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
-}
-
 int create_shared_buffer(int size, void** buffer)
 {
     int rc = syscall(SC_create_shared_buffer, size, buffer);

Libraries/LibC/unistd.h

@@ -43,7 +43,6 @@ int release_shared_buffer(int shared_buffer_id);
 int seal_shared_buffer(int shared_buffer_id);
 int get_shared_buffer_size(int shared_buffer_id);
 int set_process_icon(int icon_id);
-int read_tsc(unsigned* lsw, unsigned* msw);
 inline int getpagesize() { return 4096; }
 pid_t fork();
 int execv(const char* path, char* const argv[]);