phy: move spacemit pcie driver to its subfolder

phy: move spacemit pcie driver to its subfolder

Commit fe4bc1a08638 ("phy: spacemit: support K1 USB2.0 PHY controller")
created spacemit subfolder with usb driver while commit 57e920b92724
("phy: spacemit: Introduce PCIe/combo PHY") added pcie driver in phy
folder. Move latter into spacemit subfolder and rename file to
phy-k1-pcie.c

Reviewed-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Yixun Lan <dlan@kernel.org>
Link: https://patch.msgid.link/20260223064240.386617-1-vkoul@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>