Trying to do hello world app for Nokia 5110 LCD with arduino yun and johnny five
Arduino Yun is a ATMega32U4-based board, like other ATMega32U4-based Arduino boards, such as Arduino Leonardo, Micro, the SPI is only available on the ICSP header:

MOSI - Yun has it on ICSP Pin 4
MISO - Yun has it on ICSP Pin 1
SCK - Yun has it on ICSP pin 3
SS - Yun has no dedicated pin, use any digital data pin


You can find out the ICSP header pin assignment at Arduino SPI reference page. So here is the connection between Arduino Yun and LCD5110

Yun               LCD 5110
ICSP pin3         CLK(SCK)
ICSP pin 4        DN(MOSI)
any GPIO pin      D/C (see note 1)
RST               RST
any GPIO pin      SCE(SS) (see note 1)
any GPIO pin      Backlight (via a 330 ohm resistor) (see note 2)
GND               GND
3v3               VCC



  Note 1: Although you could use any GPIO for D/C and SCE, you should consult the library that you are using to see what pin the library used for the data/command line and SS line.
  
  Note 2: Connecting to a GPIO pin allows you to turn on and off the LED backlight, you could ignore the connection if you don't want the backlight, or you could connect it directly to 3v3 via a resistor if you want backlight on permanently


If you still have problem in using the LCD5110, please update your question with complete code and the library that you are using.