irqchip: irqc: Remove platform data support

As of commit 914d7d14 ("ARM: shmobile: r8a73a4: Remove legacy
code"), the Renesas R-Mobile/R-Car interrupt controller is used with DT
only, and interrupt numbers are thus always assigned automatically.

Drop the platform data declaration and all related support code.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1430216270-31929-1-git-send-email-geert%2Brenesas@glider.be


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>