USB: gadget: ci13xx_udc: remove unused err() macro

I previously cleaned up the err() call usage in this driver, but it
really was calling this macro instead.  To remove future confusion, just
delete this unused macro now.

Ideally, the warn() and info() macros should also be removed, and the
"real" dev_warn() and dev_info() calls should be used instead.

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>