Staging: rtl8188eu: Get rid of custom macro, DBG_88E in kmalloc

Get rid of custom macro, DBG_88E for printing message in kmalloc
in order to maintain Linux kernel coding style based on which kernel
does not print failure warning.

Issue suggested by Coccinelle.
Signed-off-by: Madhumitha Prabakaran <madhumithabiw@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/os_dep/usb_ops_linux.c

@@ -232,7 +232,6 @@ static int usbctrl_vendorreq(struct adapter *adapt, u8 request, u16 value, u16 i
 	pIo_buf = kmalloc(MAX_USB_IO_CTL_SIZE, GFP_ATOMIC);
 
 	if (!pIo_buf) {
-		DBG_88E("[%s] pIo_buf == NULL\n", __func__);
 		status = -ENOMEM;
 		goto release_mutex;
 	}