[hack] beaglebone: Clean up pinmux add regulators

Clean up pinmux:
      - Separate pinmux entries for eMMC, reset, interrrupt gpio for
      LED one into their own entries.
      - Add a pinmux node dedicated to the pins of the I2C controller
      connected to the tuner. And add this information to the tuner
      I2C controller entry.
      - Move radio tuner for the I2C3(I2C2 on schematic) to I2C2(I2C1
      on schematic)

 Add two fixed voltage dummy regulators so the driver can be tricked
 into loading.
si476x: Add IRQF_ONESHOT to irq request code

Add IRQF_ONESHOT to irq request code so that the driver can be used on
irq-chips that do not have IRQCHIP_ONESHOT_SAFE flag set.
si476x: Add simple code to allow driver to load and not crash

Add simple code to allow driver to load and not crash. Now all this
code does is sets up the reset gpio, requests IRQ and regulators.
It still does not work since the code taking into account the
differences of the command protocol is not there yet.