pinctrl: vt8500: Add VGA pins for WM8750

Add an additional 8 pins for enabling the internal VGA output of the
WM8750 SoC.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
clk: vt8500: Remove duplicate divisor adjustment in vt8500_dclk_set_rate()

The calculated divisor is already adjusted in vt8500_dclk_round_rate(), and
may be re-adjusted in set_rate due to round errors. clk_set_rate() calls
vt8500_dclk_round_rate() and adjusts the requested rate to a rounded value
that will work. We don't need to test whether the divisor is too low because
the adjustment is already made.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
fb: vt8500: Add support for VGA output on WM8750

This is a 'hacky' patch to enable video output via the VGA connector
found on the APC8750. All the new code is #ifdef'd to make it identifiable.

A new Kconfig option is added to "Enable VGA" which has the side-effect of
breaking the LCD panel output.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
dts: vt8500: Add framebuffer support for APC8750

This patch enables framebuffer support for the APC8750 via the VGA output.
A default display config of 1024x768x60 is provided, which is the default
uboot resolution.

A change to the binding is required to allow a clock to be passed to config
the pixel clock. This binding needs to be changed properly at a later time.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>