accel/tcg: Restrict page_collection structure to system TB maintainance

accel/tcg: Restrict page_collection structure to system TB maintainance

Only the system emulation part of TB maintainance uses the
page_collection structure. Restrict its declaration (and the
functions requiring it) to tb-maint.c.

Convert the 'len' argument of tb_invalidate_phys_page_fast__locked()
from signed to unsigned.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20221209093649.43738-6-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>