usb: dwc3: gadget: CSP is only valid for OUT endpoints

CSP bit is only valid for OUT endpoints. Synopsys
databook is unclear if HW ignores CSP for IN
endpoints (chances are, it does) but to avoid
problems, let's make sure to set CSP only when valid
to do so.

Change-Id: I9e4b84a5f7322c9e516b9cd64774a91e47b06c74
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Git-commit: 58f29034b4c47b202f76de055f843316c8a9325f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Mayank Rana <mrana@codeaurora.org>