ell: upgrade 0.76 -> 0.78

ell: upgrade 0.76 -> 0.78

Changelog:
==========
- ecc: Check return value of l_getrandom()
- unit: test-ecdh: Add bytes to l_getrandom wrapper
- unit: Convert UUID test cases to use precheck feature
- unit: Convert PBKDF2 test cases to use precheck feature
- unit: Convert check for random support to use test precheck feature
- unit: Make the failed precheck test case a success
- test: Add flag for indication of inverted precheck results
- unit: Use the precheck handler for testing available key support
- unit: Use the precheck handler for testing available getrandom support
- unit: Use the precheck handler for testing available checksum support
- unit: Use the precheck handler for testing available cipher support
- test: Provide test data also to the precheck function
- unit: Add test cases for precheck of unit tests
- test: Add support for precheck handler for unsupported kernel features
- Add License variable to pkg-config file

Signed-off-by: Liu Yiding <liuyd.fnst@fujitsu.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>