iommu/omap: Fix debugfs_create_*() usage

When exposing data access through debugfs, the correct
debugfs_create_*() functions must be used, depending on data type.

Remove all casts from data pointers passed to debugfs_create_*()
functions, as such casts prevent the compiler from flagging bugs.

omap_iommu.nr_tlb_entries is "int", hence casting to "u8 *" exposes only
a part of it.  Fix this by using debugfs_create_u32() instead.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Joerg Roedel <jroedel@suse.de>