ASoC: da7219: fix endianness issues

Reported by Sparse.

da7219.c:440:44: warning: cast to restricted __le16
da7219.c:461:13: warning: incorrect type in assignment (different base types)
da7219.c:461:13:    expected unsigned short [unsigned] [usertype] val
da7219.c:461:13:    got restricted __le16 [usertype] <noident>
da7219.c:1451:16: warning: incorrect type in assignment (different base types)
da7219.c:1451:16:    expected unsigned short [unsigned] [usertype] offset
da7219.c:1451:16:    got restricted __le16 [usertype] <noident>

da7219-aad.c:150:37: warning: incorrect type in assignment (different base types)
da7219-aad.c:150:37:    expected unsigned short [unsigned] [usertype] tonegen_freq_hptest
da7219-aad.c:150:37:    got restricted __le16 [usertype] <noident>
da7219-aad.c:157:37: warning: incorrect type in assignment (different base types)
da7219-aad.c:157:37:    expected unsigned short [unsigned] [usertype] tonegen_freq_hptest
da7219-aad.c:157:37:    got restricted __le16 [usertype] <noident>

Cc: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@kernel.org>