capabilities: fix undefined behavior in bit shift for CAP_TO_MASK

In the Linux kernel, the following vulnerability has been resolved:

capabilities: fix undefined behavior in bit shift for CAP_TO_MASK

Shifting signed 32-bit value by 31 bits is undefined, so changing

significant bit to unsigned. The UBSAN warning calltrace like below:

UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2

left shift of 1 by 31 places cannot be represented in type 'int'

Call Trace:

<TASK>

dump_stack_lvl+0x7d/0xa5

dump_stack+0x15/0x1b

ubsan_epilogue+0xe/0x4e

__ubsan_handle_shift_out_of_bounds+0x1e7/0x20c

cap_task_prctl+0x561/0x6f0

security_task_prctl+0x5a/0xb0

__x64_sys_prctl+0x61/0x8f0

do_syscall_64+0x58/0x80

entry_SYSCALL_64_after_hwframe+0x63/0xcd

</TASK>