Revert "genirq: Allow irq_chip registration functions to take a const irq_chip"

This reverts commit c476c5c7 which is
commit 393e1280 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: If02b4d096b62cb90fc84ec181c3b7168c1c30267
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>