drivers: reset: add Aspeed AST10x0 reset control

AST10x0 series SOCs provide the reset controller through the syscon
hardware block.  The current driver supports the reset line assert,
deassert and status for the hardware IPs embedded in the SOC.  Each
reset line has an ID that can simply map to a bit in syscon registers
RESET_CTRL0_ASSERT (group 0) or RESET_CTRL1_ASSERT (group 1). Write bits
to RESET_CTRL0_DEASSERT or RESET_CTRL1_DEASSERT will clean the
corresponding bits in RESET_CTRL0_ASSERT or RESET_CTRL1_ASSERT
registers.

Signed-off-by: Dylan Hung <dylan_hung@aspeedtech.com>