Delete ARM's asm/system.h.  It's the last holdout and should be got rid of.

This builds for defconfig, lpc32xx_defconfig, exynos_defconfig + XEN, the
previous changed to a Gemini system and an omap3 config with TI_DAVINCI_EMAC.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>