kernel, ksud: clean headers and add fd wrapper for devpts (#193)

* Now Official KernelSU devpts compat is questionable
Squashed commits:
4893fad235
e7c3d4a6a6
4bb2dae3f5

Signed-off-by: Faris <rissu.ntk@gmail.com>
Co-authored-by: 5ec1cff <56485584+5ec1cff@users.noreply.github.com>
Co-authored-by: weishu <twsxtd@gmail.com>
Co-authored-by: backslashxx <118538522+backslashxx@users.noreply.github.com>

kernel/arch.h

@@ -70,7 +70,7 @@
 #endif
 
 #else
-#ifdef CONFIG_KSU_KPROBES_HOOK
+#ifdef KSU_KPROBES_HOOK
 #error "Unsupported arch"
 #endif
 #endif