On some systems (at least Windows/CYGWIN and macOS) libusb_dev_mem_alloc()
simply returns NULL. The helper can fall-back to malloc() to allocate
CMSIS-DAP pending command/response buffers.
Fixes: fd75e9e542 (jtag/drivers/cmsis_dap_bulk: use asynchronous libusb transfer)
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Change-Id: I89660f6747ad9d494b8192711cbbee5764e058fa
Reviewed-on: https://review.openocd.org/c/openocd/+/8044
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins
44e02e1f49