Recent changes caused that the HMI10 board now is included in the
boards built by MAKEALL, which revealed that compilation for this
board has been broken for a long time:

ps2ser.c: In function 'ps2ser_init':
ps2ser.c:155: error: 'UART_LCR' undeclared (first use in this function)
ps2ser.c:155: error: (Each undeclared identifier is reported only once
ps2ser.c:155: error: for each function it appears in.)
ps2ser.c:156: error: 'UART_DLL' undeclared (first use in this function)
ps2ser.c:157: error: 'UART_DLM' undeclared (first use in this function)
ps2ser.c:159: error: 'UART_IER' undeclared (first use in this function)
ps2ser.c:160: error: 'UART_MCR' undeclared (first use in this function)
ps2ser.c:161: error: 'UART_FCR' undeclared (first use in this function)
ps2ser.c:162: error: 'UART_FCR_ENABLE_FIFO' undeclared (first use in this function)
ps2ser.c:166: error: 'UART_LSR' undeclared (first use in this function)
ps2ser.c: In function 'ps2ser_putc':
ps2ser.c:198: error: 'UART_LSR' undeclared (first use in this function)
ps2ser.c:200: error: 'UART_TX' undeclared (first use in this function)
ps2ser.c: In function 'ps2ser_getc_hw':
ps2ser.c:224: error: 'UART_LSR' undeclared (first use in this function)
ps2ser.c:225: error: 'UART_RX' undeclared (first use in this function)
ps2ser.c: In function 'ps2ser_interrupt':
ps2ser.c:293: error: 'UART_IIR' undeclared (first use in this function)

The board is orphaned, and AFAICT has reached EOL.
Drop support for it.

Signed-off-by: Wolfgang Denk <wd@denx.de>