librbd: use 64-bits to shift order

librbd: use 64-bits to shift order

Order is never actually this high currently, but it be via librbd.

CID 716937: Overflowed return value (INTEGER_OVERFLOW)
At (3): Overflowed or truncated value (or a value computed from an
overflowed or truncated value) "offset" used as return value.

CID 717012: Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
At (1): Potentially overflowing expression "1 << obj_order" with type
"int" (32 bits, signed) is evaluated using 32-bit arithmetic before
being used in a context which expects an expression of type "uint64_t"
(64 bits, unsigned). To avoid overflow, cast the left operand to
"uint64_t" before performing the left shift.

CID 717011: Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
At (1): Potentially overflowing expression "1 << order" with type
"int" (32 bits, signed) is evaluated using 32-bit arithmetic before
being used in a context which expects an expression of type "uint64_t"
(64 bits, unsigned). To avoid overflow, cast the left operand to
"uint64_t" before performing the left shift.

CID 717013: Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
At (1): Potentially overflowing expression "1 << order" with type
"int" (32 bits, signed) is evaluated using 32-bit arithmetic before
being used in a context which expects an expression of type "uint64_t"
(64 bits, unsigned). To avoid overflow, cast the left operand to
"uint64_t" before performing the left shift.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>