samsung-zeroltexx: Fix audio (fix memory alignment problem)

samsung-zeroltexx: Fix audio (fix memory alignment issue that led to crashes).

The compile switches relating to memory alignment seem necessary to prevent a crash in DMA transfers (gcc6 instead of gcc10 would also have fixed this; cf. my earlier comment in !2105 (comment 593597958)).

Alsa audio playback works fine after this fix. I have not yet fully figured out the mixer functionality (>700 controls!) yet, but with these example commands, audio output is routed to the earpiece:

# Audio on receiver:
amixer cset name='HPOUT3L Input 1' AIF1RX1
amixer cset name='HPOUT3 Digital Switch' on,on

aplay /usr/share/sounds/alsa/Front_Center.wav

With this example, audio output is routed to the speaker:

# Audio on Speaker:
amixer cset name="AIF4TX1 Input 2" AIF1RX1
amixer cset name="AIF4TX2 Input 2" AIF1RX2
amixer cset name='SPK Enable Switch' Enable
amixer cset name='SPK Switch' on
amixer cset name='SPK out' 1

echo "Hello, World!" | flite