accel/tcg: Rename CPUIOTLBEntry to CPUTLBEntryFull

This structure will shortly contain more than just
data for accessing MMIO.  Rename the 'addr' member
to 'xlat_section' to more clearly indicate its purpose.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>