soc: fsl: qe: remove unused qe_ic_set_* functions

There are no current callers of these functions, and they use the
ppc-specific virq_to_hw(). So removing them gets us one step closer to
building QE support for ARM.

If the functionality is ever actually needed, the code can be dug out
of git and then adapted to work on all architectures, but for future
reference please note that I believe qe_ic_set_priority is buggy: The
"priority < 4" should be "priority <= 4", and in the else branch 24
should be replaced by 28, at least if I'm reading the data sheet right.

Reviewed-by: Timur Tabi <timur@kernel.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Li Yang <leoyang.li@nxp.com>