Fixes for checkstyle

Exclude rpcgen generated files from cstyle check and
add gitignore for rpcgen created files.

Signed-off-by: Andrew Walker <awalker@ixsystems.com>

.gitignore

@@ -31,6 +31,8 @@
 modules.order
 Makefile
 Makefile.in
+nfs41acl.h
+nfs41acl_xdr.c
 
 #
 # Top level generated files specific to this top level dir

Makefile.am

@@ -117,6 +117,7 @@ cstyle:
 	@find ${top_srcdir} -name build -prune -o -name zfsd -prune \
 		-o -type f -name '*.[hc]' \
 		! -name 'zfs_config.*' ! -name '*.mod.c' \
+		! -name 'nfs41acl_xdr.c' ! -name 'nfs41acl.h' \
 		! -name 'opt_global.h' ! -name '*_if*.h' \
 		! -path './module/zstd/lib/*' \
 		-exec ${top_srcdir}/scripts/cstyle.pl -cpP {} \+