clk: spacemit: mark K1 pll1_d8 as critical

In the Linux kernel, the following vulnerability has been resolved:

clk: spacemit: mark K1 pll1_d8 as critical

The pll1_d8 clock is enabled by the boot loader, and is ultimately a
parent for numerous clocks, including those used by APB and AXI buses.
Guodong Xu discovered that this clock got disabled while responding to
getting -EPROBE_DEFER when requesting a reset controller.

The needed clock (CLK_DMA, along with its parents) had already been
enabled. To respond to the probe deferral return, the CLK_DMA clock
was disabled, and this led to parent clocks also reducing their enable
count. When the enable count for pll1_d8 was decremented it became 0,
which caused it to be disabled. This led to a system hang.

Marking that clock critical resolves this by preventing it from being
disabled.

Define a new macro CCU_FACTOR_GATE_DEFINE() to allow clock flags to
be supplied for a CCU_FACTOR_GATE clock.