Fix grammar

The verb 'suggest' is used with the gerund form.

Author: visitorckw

lkmpg.tex

@@ -675,7 +675,7 @@ \subsection{Building modules for a precompiled kernel}
 \end{verbatim}
 
 In this case, you need to restore the value of symbol \textbf{EXTRAVERSION} to \textbf{-rc2}.
-We suggest to keep a backup copy of the makefile used to compile your kernel available in \verb|/lib/modules/5.14.0-rc2/build|.
+We suggest keeping a backup copy of the makefile used to compile your kernel available in \verb|/lib/modules/5.14.0-rc2/build|.
 A simple command as following should suffice.
 \begin{codebash}
 cp /lib/modules/`uname -r`/build/Makefile linux-`uname -r`