dm: timer: uclass: Add flag to control sequence numbering

dm: timer: uclass: Add flag to control sequence numbering

Like SPI and I2C, timer devices also have multiple chip
instances. This patch adds the flag 'DM_UC_FLAG_SEQ_ALIAS' in
timer_uclass driver to control device sequence numbering.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>