ep93xx: Don't use system controller defines in audio drivers

Both the Snapper CL15 and EDB93xx audio drivers set the same audio
configuration in ep93xx_i2s_acquire. Remove the arguments to
ep93xx_i2s_acquire so that the audio drivers no longer need the
EP93XX_SYSCON defines exported.

Cc: Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Mika Westerberg <mika.westerberg@iki.fi>
Cc: Liam Girdwood <lrg@ti.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>