GitLab

System config block contains hardware unrelated to USB.  So calling
`__SYSCFG_CLK_DISABLE()` during `HAL_PCD_MspDeInit()` has an adverse effect
on other system functionality.

Removing call to `__SYSCFG_CLK_DISABLE()` to rectify this issue.

This call was there since the beginning of the USB CDC code, added in
b30c02af.