ext/hls/meson.build: fix dependency logic
Currently, if one was to set -Dhls-crypto to either libgcrypt or openssl instead of auto, the following lines would fail because hls_crypto_dep is not yet set:
if not hls_crypto_dep.found() and ['auto', 'libgcrypt'].contains(hls_crypto) if not hls_crypto_dep.found() and ['auto', 'openssl'].contains(hls_crypto)
Instead, change "if not hls_crypto_dep.found()" to "if not have_hls_crypto" which fixes the error.