tools/power turbostat: Fix build with musl

turbostat.c: In function 'parse_int_file':
turbostat.c:5567:19: error: 'PATH_MAX' undeclared (first use in this function)
5567 | char path[PATH_MAX];
| ^~~~~~~~

turbostat.c: In function 'probe_graphics':
turbostat.c:6787:19: error: 'PATH_MAX' undeclared (first use in this function)
6787 | char path[PATH_MAX];
| ^~~~~~~~

Signed-off-by: Calvin Owens <[e-mail]>
Reviewed-by: Artem Bityutskiy <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

tools/power/x86/turbostat/turbostat.c

···
 #include <stdbool.h>
 #include <assert.h>
 #include <linux/kernel.h>
+#include <limits.h>
 
 #define UNUSED(x) (void)(x)