configs/z80sim and xtrs: Serial driver lower halfs ioctl methods should return a negated errno value, not set the errno variable.
drivers/wireless: CC1101 driver not permitted to set errno.
drivers/sensors: LIS331DL driver not permitted to set errno.
drivers/lcd: ILI9341 initialize method not permitted to set errno,
drivers/serial: 16550 UART driver IOCTL method must not set errno; it must return a negated errno value.
Entropy pool gathers environmental noise from device drivers, user-space, etc., and returns good random numbers, suitable for cryptographic use. Based on entropy pool design from *BSDs and uses BLAKE2Xs algorithm for CSPRNG output.
Patch also adds /dev/urandom support for using entropy pool RNG and new 'getrandom' system call for getting randomness without file-descriptor usage (thus avoiding file-descriptor exhaustion attacks). The 'getrandom' interface is similar as 'getentropy' and 'getrandom' available on OpenBSD and Linux respectively.
