Cast the integer read as the first argument for %b to an unsigned integer

Cast the integer read as the first argument for %b to an unsigned integer
so it's value is not sign extended when assigned to the uintmax_t variable
used internally by printf.  For example, if bit 31 is set in the cpuid
feature word, then %b would print out the initial value as a 16 character
hexadecimal value.  Now it only prints out an 8 character value.

Reviewed by:	bde