These error checks are implemented in regmap core. Remove the duplicate
code from regmap-mmio.c
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

Some of the error conditions detected by regmap_mmio_*() are pure internal
errors, rather than user-/client-triggerable conditions. Convert these to
BUG().
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

This is a basic memory-mapped-IO bus for regmap. It has the following
features and limitations:

* Registers themselves may be 8, 16, 32, or 64-bit. 64-bit is only
  supported on 64-bit platforms.
* Register offsets are limited to precisely 32-bit.
* IO is performed using readl/writel, with no provision for using the
  __raw_readl or readl_relaxed variants.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>