docs: fix $(PKG)_SITE_METHOD names (UPPER CASE => lower case)

Currently, the documentation says $(PKG)_SITE_METHOD should have upper
case names such as SVN or GIT, but the implementation only accepts lower
case svn or git. This fixes the documentation.

Signed-off-by: Bjørn Forsman <bjorn.forsman@gmail.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Daniel Nyström <daniel.nystrom@timeterminal.se>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

docs/buildroot.html

@@ -1060,17 +1060,17 @@ $(eval $(call GENTARGETS,package,libfoo,host))
 
       <li><code>LIBFOO_SITE_METHOD</code> may contain the method to
       fetch the package source code. It can either
-      be <code>WGET</code> (for normal FTP/HTTP downloads of
-      tarballs), <code>SVN</code> or <code>GIT</code>. When not
+      be <code>wget</code> (for normal FTP/HTTP downloads of
+      tarballs), <code>svn</code> or <code>git</code>. When not
       specified, it is guessed from the URL given
       in <code>LIBFOO_SITE</code>: <code>git://</code>
-      and <code>svn://</code> URLs will use the <code>GIT</code>
-      and <code>SVN</code> methods respectively. All other URL-types
-      will use the <code>WGET</code> method. So for example, in the
+      and <code>svn://</code> URLs will use the <code>git</code>
+      and <code>svn</code> methods respectively. All other URL-types
+      will use the <code>wget</code> method. So for example, in the
       case of a package whose source code is available through
       Subversion repository on HTTP, one <i>must</i>
-      specifiy <code>LIBFOO_SITE_METHOD=SVN</code>. For <code>SVN</code>
-      and <code>GIT</code> methods, what Buildroot does is a
+      specifiy <code>LIBFOO_SITE_METHOD=svn</code>. For <code>svn</code>
+      and <code>git</code> methods, what Buildroot does is a
       checkout/clone of the repository which is then tarballed and
       stored into the download cache. Next builds will not
       checkout/clone again, but will use the tarball