usb: chipidea: Fix oops when removing the ci_hdrc module

The call of 'kfree(ci->hw_bank.regmap)' in ci_hdrc_remove() sometimes causes
a kernel oops when removing the ci_hdrc module.

Since there is no separate memory allocated for the ci->hw_bank.regmap array,
there is no need to free it.

Cc: v3.14+ <stable@@vger.kernel.org>
Signed-off-by: Torsten Fleischer <to-fleischer@t-online.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>