New Port: Eros Q Native

What works:
- LCD: 16-bit RGB565
- all buttons, including scrollwheel
- SD Card
- Battery level and charging/not charging status
- USB
- audio
- sample rate switching
- HP / LO detect, with "safe" fixed LO volume -
   LO volume will only be put to user-defined max volume
   if headphones are not present.
- rtc
- Plugins build, tried a couple and they seem OK
- Bootloader, installable to nand via usbboot

What doesn't work:
- Dual Boot
- power on/off has intermittent, low volume audio click
   (sometimes it's completely silent, sometimes there's
    a click)
- Audio uses 16-bit volume scaling, so clicking/popping
   is pretty bad at lower volumes - need 32 bit volume
   scaling, 24 bit I2S data
- USB HID keys not yet defined
- no jztool support

Unknowns:
- Stereo Switch pins: Direction select, AC_DC
   (probably not even hooked up)
- What is the actual purpose of the Stereo Swtich?
- How does the bluetooth module connect?

"Someday" stuff:
- get LCD working at higher bit depth
- Bluetooth

Change-Id: I70dda8fc092c6e3f4352f2245e4164193f803c33

firmware/export/audiohw.h

@@ -210,6 +210,8 @@ struct sound_settings_info
 #include "df1704.h"
 #elif defined(HAVE_PCM1792_CODEC)
 #include "pcm1792.h"
+#elif defined(HAVE_EROS_QN_CODEC)
+#include "eros_qn_codec.h"
 #elif defined(HAVE_NWZ_LINUX_CODEC)
 #include "nwzlinux_codec.h"
 #elif defined(HAVE_CS4398)