Rename several functions, dropping "generic" and making "host"
vs "target" clearer.  Make a bunch of functions static that are
not used outside this file. Replace INIT_DISASSEMBLE_INFO with
a trio of functions.

Acked-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>