inotify-tools: update license information

Explicitly indicate that this package is GPL v2.0+ as well as
provide a hash for the source's license file (COPYING).

Signed-off-by: James Knight <james.d.knight@live.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/inotify-tools/inotify-tools.hash

@@ -1,2 +1,3 @@
 # Locally computed
 sha256 a433cc1dedba851078276db69b0e97f9fe41e4ba3336d2971adfca4b3a6242ac inotify-tools-3.20.1.tar.gz
+sha256 e41fc126320a79ed53b5aa3386f059f7d10770856d6fd714ab80a96ce6bd09d6 COPYING

package/inotify-tools/inotify-tools.mk

@@ -6,7 +6,7 @@
 
 INOTIFY_TOOLS_VERSION = 3.20.1
 INOTIFY_TOOLS_SITE = $(call github,rvoicilas,inotify-tools,$(INOTIFY_TOOLS_VERSION))
-INOTIFY_TOOLS_LICENSE = GPL
+INOTIFY_TOOLS_LICENSE = GPL-2.0+
 INOTIFY_TOOLS_LICENSE_FILES = COPYING
 INOTIFY_TOOLS_INSTALL_STAGING = YES
 INOTIFY_TOOLS_AUTORECONF = YES