Add Gravis GamePad Pro USB key layout

# Gravis GamePad Pro USB

# Yellow

key 0x131   BUTTON_A

# Green

key 0x132   BUTTON_B

# Red

key 0x130   BUTTON_X

# Blue

key 0x133   BUTTON_Y

# Left Upper Shoulder "1"

key 0x134   BUTTON_L1

# Right Upper Shoulder "1"

key 0x135   BUTTON_R1

# Left Lower Shoulder "2"

key 0x136   BUTTON_L2

# Right Lower Shoulder "2"

key 0x137   BUTTON_R2

# Select & Start

key 0x138   BUTTON_SELECT

key 0x139   BUTTON_START

# D-Pad

axis 0x00   HAT_X

axis 0x01   HAT_Y