target/hppa: Add install_iaq_entries

target/hppa: Add install_iaq_entries

Instead of two separate cpu_iaoq_entry calls, use one call to update
both IAQ_Front and IAQ_Back.  Simplify with an argument combination
that automatically handles a simple increment from Front to Back.

Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>