Revert "README: Added the information for the support of Linux 4.9 (#103)"

This reverts commit f8583fbef0.

README.md

@@ -21,11 +21,7 @@ Now KernelSU will work on these version of kernels without any modification：
 - `5.10`
 - `5.4`
 - `4.19`
-
-Moreover, KernelSU will work on these version of kernels with the modification of kernel source code:
-
 - `4.14`
-- `4.9`
 
 And the current supported ABIs are : `arm64-v8a` & `x86_64`
 

README_CN.md

@@ -21,11 +21,7 @@ KernelSU 还处于早期开发阶段，你不应该生产环境中使用它。Ke
 - `5.10`
 - `5.4`
 - `4.19`
-
-除此之外，KernelSU 还可以在这些版本的内核上正常工作，但需要对内核源码进行一定的修改：
-
 - `4.14`
-- `4.9`
 
 目前支持架构 : `arm64-v8a` & `x86_64`