bus: vexpress-config: Add missing MODULE_DESCRIPTION() macro

With ARCH=arm64, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/bus/vexpress-config.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240613-md-arm64-drivers-bus-v1-1-e8162434e0ca@quicinc.com


Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>