Per your descriptions, the BCM53108 is our multiport 10/100Mbps Ethernet Switch and it is [8FE port + one RGMII/GMII/MII/RvMII/TMII/RvTMII uplink port] Switch.
Suggest the alternative chip for your case is our the other multiport Gigabit Ethernet Switch BCM53128, BCM53128 is [8GE port + one RGMII/GMII/MII/RvMII/TMII/RvTMII uplink port] Switch.
BCM53128 is pin to pin compatible with BCM53108
But when you change chip to BCM53128 on your BCM53108 board, it requires to use your SW to configure BCM53128 registers Reg(0x10-0x17: 0x12) bit[9:8]=00 via SPI to disable the front ports 1000BASE-T capability.
Please let me know if there is any questions.