Revert "serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES"

Revert "serial: uartps: Do not allow use aliases >= MAX_UART_INSTANCES"

BugLink: https://bugs.launchpad.net/bugs/1876361
commit 91c9dfa25c7f95b543c280e0edf1fd8de6e90985 upstream.

This reverts commit 2088cfd882d0403609bdf426e9b24372fe1b8337.

As Johan says, this driver needs a lot more work and these changes are
only going in the wrong direction:
  https://lkml.kernel.org/r/20190523091839.GC568@localhost

Reported-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/dac3898e3e32d963f357fb436ac9a7ac3cbcf933.1585905873.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>