Update script syntax errors on older Pi models

[brookst]

Running the latest rpi-eeprom-update on older Raspberry Pis gives the error:

/usr/bin/rpi-eeprom-update: 273: /usr/bin/rpi-eeprom-update: arithmetic expression: expecting ')': "(0x00*
0f >> 23) & 1"

This is due to hexdump eliding zeros in its output. I have boards with a BOARD_INFO of 0x00000002 and 0x0000000f. These get an asterisk and newline inserted by hexdump as above. All that's needed is to pass the -v flag to emit all output. Line 271 of rpi-eeprom-update is where this error occurs but I haven't checked if there are any other uses like this.