ARM: realview: clean up header files

This contains multiple trivial cleanups to the realview headers:

- removing the file names from the introductory comment
- removing the uncompress.h header that is unused
- removing the irqs.h header and NR_IRQS logic that is
  obsoleted by sparse IRQs

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>