USB: Keep hs_pclk during LPM, cleanup.

Drop Acer workaround for USB suspend and redundant IRQ.
Keep hs_pclk clock enabled to sense wall charge plug in/out, shutting down
hs_pclk immediately switches OTGSC_BSV bit off and that shuts down USB charging.
See CodeAurora kernel/msm commit 4f196e9119b3f7686cb575d1efd8912031556cb1 for
hs_pclk workaround description.

Magically fixes #12
AUO LCDC: Don't set backlight function

Get rid of CONFIG_MACH_ACER_A1 guards around backlight code, use FB_BACKLIGHT
but not define the backlight function. Basically that gives us the same thing.
While I am there, retitle AUO config option and fix the Kconfig warning.