sunxi-disp: Allow build without axp

I wrote this patch while working on A10s support, then when I tried to
get my Olinuxino A13_Micro running using commits from
https://github.com/hehopmajieh/linux-sunxi/

I noticed a similar patch there:
https://github.com/hehopmajieh/linux-sunxi/commit/e7c1fc23a723bdf799c0aef02920b55650c06e12

But I believe this fix is better because:
1) It properly checks for CONFIG_AXP rather then CONFIG_POWER, as the former
can still be unset when the latter is set
2) Rather then just ignoring axp gpio calls when not build with axp support
it complains loudly when other code tries to use axp gpio-s when built without

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi-disp: Don't crash on sun5i when screen0_output_type == vga

I was (wrongly) trying to set screen0_output_type to vga for the
Olinuxino A13_Micro (the Olinuxino A13 * uses LCD output + some external
logic for VGA-out).

This leads to a NULL ref due to the sunxi-disp-vga code containing some
special handling for composite out which tries to set up dac parameters
on the 2nd tv-encoder. *But* the sun5i only has 1 tv-encoder.

Even though this was mainly caused by a wrong fex file I'm still submitting
this patch, because the A10s does have a fully functional display block,
which likely does support VGA out.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Add AXP 15 power module for A10s Chips

HdG: Note as usual with code imported from the sunxi SDK there are severe
style issues :|

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
axp15: Hookup the axp152 code

HdG: Fixed some checkpatch warnings

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
mach-sun5i: Remove bogus debug-uart device

I encountered this while testing my A10s TV-stick, which uses uart0 for
its uart test-pads.

Having this device always registered + uart0_used set in the fex file,
caused 2 uart driver to get registered for uart0, both the regular
serial8250 as well as the 8250-sunxi driver, then when the first uart0
interrupt happens things go boom.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>