package/libsrtp: fix license hash

While bumping the package from 1.5.4 to 2.2.0 the license hash from
version 1.6.0 was erroneously used.

Fixes
http://autobuild.buildroot.net/results/2d8/2d8344bab5b87d20156814b96cbbab1d5fc89586/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libsrtp/libsrtp.hash

@@ -1,3 +1,3 @@
 # Locally calculated
 sha256 44fd7497bce78767e96b54a11bca520adb2ad32effd515f04bce602b60a1a50b  libsrtp-v2.2.0.tar.gz
-sha256 8defed37d52096ae14b60adc499c33d43975109bc265552ee67e9a888c634b93  LICENSE
+sha256 8e19d42a1eec9561f3f347253ddf2e385c55f392f025bb0fd41b88dbf38db5ae  LICENSE