arm side of aica(4) sometimes became unresponsive when audioplay was performed several times.

- disabled data cache at startup.
- compiled with cross-arm-none-eabi-gcc-8.3.0nb4 of pkg.
- added memse

arm side of aica(4) sometimes became unresponsive when audioplay was performed several times.

- disabled data cache at startup.
- compiled with cross-arm-none-eabi-gcc-8.3.0nb4 of pkg.
- added memset() in asm because gcc8 (and later) detects the zero clear part in
own bzero function and calls memset internally, and bzero were replaced with memset.

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don't use tsleep() in interrupt context.
when the audio starts playing, initialization is performed on the aica arm driver side.

s/u_intN_t/uintN_t/

merge ktrace-lwp.

Make sure the string dollar NetBSD doller is stored literally.

Added AICA sound driver contributed by Ryo Shimizu.