Revert "of: base: Introduce of_alias_get_alias_list() to check alias IDs"

This reverts commit b1078c35.

The single user of of_alias_get_alias_list(),
drivers/tty/serial/xilinx_uartps.c, has since been refactored and no
longer needs this function. It also contained a Smatch checker warning:

 drivers/of/base.c:2038 of_alias_get_alias_list()
 warn: passing negative bit value 's32min-(-2),0-s32max' to 'set_bit()'

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rob Herring <robh@kernel.org>