iommu/shmobile: Remove unused Renesas IPMMU/IPMMUI driver

As of commit 44d88c75 ("ARM: shmobile: Remove legacy SoC code
for R-Mobile A1"), the Renesas IPMMU/IPMMUI driver is no longer used.
In theory it could still be used on SH-Mobile AG5 and R-Mobile A1 SoCs,
but that requires adding DT support to the driver, which is not
planned.

Remove the driver, it can be resurrected from git history when needed.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Joerg Roedel <jroedel@suse.de>