tools: change cpumaps to uint8_t

tools: change cpumaps to uint8_t

Cpumap types in tools (libxc and libxl) are changed to be based on bytes like
in the interface to the hypervisor.
To make handling easier the size of used cpumaps is always based on the
number of physical cpus supported by the hypervisor. This eliminates the need
to keep track of the cpumap size in external interfaces.
In libxl a macro for cycling through a cpumap is added (libxl_for_each_cpu).

Interfaces changed:
libxl_set_vcpuaffinity()
libxl_cpumap_alloc()
xc_vcpu_setaffinity()
xc_vcpu_getaffinity()
xc_cpupool_freeinfo()

Signed-off-by: Juergen Gross <juergen.gross@ts.fujitsu.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>