Staging: bcm: Clean up patch that calls semaphore down_trylock directly.

This patch evaluates/calls the down_trylock locking
function directly, instead of storing the results
in a variable and evaluating the variable. These
changes were made in:
IOCTL_BCM_BUFFER_DOWNLOAD_STOP and
IOCTL_BCM_BUFFER_DOWNLOAD_START.

Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>