configure: use use_pkg_config() instead of check_pkg_config() for libsmbclient

This ensures that the CFLAGS and LDFLAGS are actually applied.
Fixes an incorrect change introduced with the clean-up in commit
cfcaf6b38e.

Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -4887,7 +4887,7 @@ enabled libquvi           && require_pkg_config libquvi quvi/quvi.h quvi_init
 enabled librtmp           && require_pkg_config librtmp librtmp/rtmp.h RTMP_Socket
 enabled libschroedinger   && require_pkg_config schroedinger-1.0 schroedinger/schro.h schro_init
 enabled libshine          && require_pkg_config shine shine/layer3.h shine_encode_buffer
-enabled libsmbclient      && { check_pkg_config smbclient libsmbclient.h smbc_init ||
+enabled libsmbclient      && { use_pkg_config smbclient libsmbclient.h smbc_init ||
                                require smbclient libsmbclient.h smbc_init -lsmbclient; }
 enabled libsoxr           && require libsoxr soxr.h soxr_create -lsoxr
 enabled libssh            && require_pkg_config libssh libssh/sftp.h sftp_init