examples: Fix device handle leak in xusb

examples: Fix device handle leak in xusb

The CALL_CHECK macro returns from the current function, so in the
test_device() function the device handle was being leaked when one of
the functions failed. This commit adds a new CALL_CHECK_CLOSE macro that
does the same as CALL_CHECK but also closes the device handle before
returning. In addition, the macros are changed to declare their needed
variable rather than relying on the variable to already exist within the
scope of the function.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>