rpcd: Explicitly link with lcrypt
Fixes build issues with some toolchains that don't add lcrypt in the default
search paths:
CMakeFiles/rpcd.dir/session.c.o: In function `rpc_login_test_password':
build_dir/target-mipsel-linux-gnu/rpcd-2016-12-03-0577cfc1/session.c:823: undefined reference to `crypt'
collect2: error: ld returned 1 exit status
Signed-off-by: Florian Fainelli <[email protected]>
Florian Fainelli