dt-bindings: clock: spacemit: CLK_SSPA_I2S_BCLK for SSPA

dt-bindings: clock: spacemit: CLK_SSPA_I2S_BCLK for SSPA

In order to use the virtual clock SSPAx_I2S_BCLK in the device tree and
register it in the driver, this patch introduces the macro definition.

Fixes: 1b72c59db0add ("clk: spacemit: Add clock support for SpacemiT K1 SoC")
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Link: https://lore.kernel.org/r/20250811-k1-clk-i2s-v5-1-ebadd06e1e91@linux.spacemit.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>