regmap: Move tracing header into drivers/base/regmap

The tracing events for regmap are confined to the regmap subsystem. It
also requires accessing an internal header. Instead of including the
internal header from a generic file location, move the tracing file
into the regmap directory.

Also rename the regmap tracing header to trace.h, as it is redundant to
keep the regmap.h name when it is in the regmap directory.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Mark Brown <broonie@kernel.org>