ALSA: hdsp: Make uapi/hdsp.h compilable again

Recently alsa-lib updated its content of sound/hdsp.h just by copying
the latest Linus kernel uapi/*.h, and this broke the build of
alsa-tools programs.  We used to modify the headers so that they can
be built without asoundlib.h and linux kernel headers, and the
verbatim copy doesn't work as is.

This patch removes again the linux/types.h inclusion and drop __user
prefix that broke the build and adjusts the corresponding code.

Link: https://lore.kernel.org/r/20191220153415.2740-3-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>