Audioinjector Octo : add extra sample rates, fix rst and use bcm270x regs

This patch adds new sample rates to the Audioinjector Octo sound card. The
new supported rates are (in kHz) :
96, 48, 32, 24, 16, 8, 88.2, 44.1, 29.4, 22.05, 14.7

This patch also replaces the regulators in the device tree overlay with
the ones declared in bcm270x.dtsi include file.

This patch also adds an extra codec reset and delay on probe.