alsa-utils: fixup ncurses config script

Point the build to the proper (which BTW was broken since it pointed to
the wrong directory) ncurses config by using $(NCURSES_CONFIG_SCRIPTS)
from the ncurses package directly.
Also select the proper variant (widec/non-widec) in configure.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>