soc: qcom: tracer_pkt: Add necessary timer include

The tracer packet driver currently uses functions from asm/arch_timer.h, a
header file which is not included in the tracer packet driver. This can
cause compilation errors on some architectures.

Include the necessary header file to allow compilation of the driver on
all architectures.

Change-Id: Ia836a4c1dc2ede993ce0528491792fcc92a28b6d
Signed-off-by: Steven Cahail <scahail@codeaurora.org>