tools/automake: Revert "Do not use $(V) - force AM_V=1"

This reverts commit 43365ca662 ("Do not use $(V) - force AM_V=1") as
it breaks verbose output in automake packages, deviating from the
upstream and expected behaviour.

As you can see, neither make command outputs the expected verbose
compile command lines:

```
$ make package/mtd-utils/{clean,compile} V=sc
...
  CCLD     lsmtd
  CC       nand-utils/nanddump.o
  CCLD     nanddump
...
```
```
$ make -C build_dir/target*/mtd-utils-2.1.1 clean
...
$ make -C build_dir/target*/mtd-utils-2.1.1 V=1
...
  CC       lib/libmtd.o
  CC       lib/libfec.o
  CC       lib/common.o
  CC       lib/libcrc32.o
```

The original reason for this commit was some packages failing to build
if V is set to something other than 0 or 1. See the discussion in PR
https://github.com/openwrt/openwrt/pull/2481 for how to fix this in the
package Makefile.

Ref: PR#2481
Acked-by: Mirko Vogt <mirko-openwrt@nanl.de>
Signed-off-by: Fredrik Olofsson <fredrik.olofsson@anyfinetworks.com>
[commit title/description facelift]
Signed-off-by: Petr Štetiar <ynezz@true.cz>

tools/automake/patches/200-do-not-override-silent-rules.patch

@@ -1,13 +0,0 @@
-diff -ruN automake-1.15/m4/silent.m4 automake-1.15.mod/m4/silent.m4
---- automake-1.15/m4/silent.m4	2014-12-30 22:53:05.000000000 +0100
-+++ automake-1.15.mod/m4/silent.m4	2015-03-11 12:00:26.280586399 +0100
-@@ -41,7 +41,8 @@
- else
-   am_cv_make_support_nested_variables=no
- fi])
--if test $am_cv_make_support_nested_variables = yes; then
-+#if test $am_cv_make_support_nested_variables = yes; then
-+if false; then
-   dnl Using '$V' instead of '$(V)' breaks IRIX make.
-   AM_V='$(V)'
-   AM_DEFAULT_V='$(AM_DEFAULT_VERBOSITY)'