musb_hdrc: Various bugfixes and other updates

Various bugfixes:
    - gadget side does dma_sync_single_for_*() if the buffer
      was mapped by the gadget driver (none do that just yet)
    - host side rx, always force dma request off "just in case",
      instead of just for Mentor's DMA (i.e. not just OMAP2430)
    - complain louder about the board needing different driver config
    - iounmap() registers on rmmod
    - fault handling fixes in tusb_start()
    - (from TI) save dma mask so modprobe after use_dma=n can use dma
    - (from TI) gadget side zero-length IN likes TXPKTRDY before status stage

Other updates:
    - catch up to pt_regs finally leaving the irq path, other build fixes
    - remove pointless headers like <linux/pci.h>
    - RemoveMoreCamelCaseNastiness
    - resolve some config-specific compiler warning/error messages
    - dump tusb irq status register too
    - remove that MIN_DMA thing; dma logic must now handle zlps
      in all cases, not just to terminate a transfer
    - comment fixes

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>