clk: spacemit: fix sspax_clk

clk: spacemit: fix sspax_clk

Hardware Requirement:

BIT[3] of this register must be set if need to select i2s_bclk as
SSPA parent clock, to solve this, introduces a new SSPAx_I2S_BCLK
clock as the virtual gate clock.

Fixes: 1b72c59db0add ("clk: spacemit: Add clock support for SpacemiT K1 SoC")
Suggested-by: Yao Zi <ziyao@disroot.org>
Reviewed-by: Haylen Chu <heylenay@4d2.org>
Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Link: https://lore.kernel.org/r/20250811-k1-clk-i2s-v5-2-ebadd06e1e91@linux.spacemit.com
Signed-off-by: Yixun Lan <dlan@gentoo.org>