ARM: 9449/1: coresight: Finish removal of Coresight support in arch/arm/kernel

Commit 184901a0 ("ARM: removing support for etb/etm in
"arch/arm/kernel/"") removed asm/hardware/coresight.h which is included
by this file. Therefore this is dead code so delete it.

Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>