target/arm: Move cortex sysregs into a separate file

target/arm: Move cortex sysregs into a separate file

The file cpu_tcg.c is about to be moved into the tcg/ directory, so
move the register definitions into a new file.

Also move the function declaration to the more appropriate cpregs.h.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230426180013.14814-2-farosas@suse.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>