nvme: Split out PCI support

Apple SoCs have an integrated NVMe controller that isn't connected
over a PCIe bus. In preparation for adding support for this NVMe
controller, split out the PCI support into its own file. This file
is selected through a new CONFIG_NVME_PCI Kconfig option, so do
a wholesale replacement of CONFIG_NVME with CONFIG_NVME_PCI.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested on: Macbook Air M1
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/rcar3_salvator-x_defconfig b/configs/rcar3_salvator-x_defconfig
index f60ddf0..d4dc8ec 100644
--- a/configs/rcar3_salvator-x_defconfig
+++ b/configs/rcar3_salvator-x_defconfig
@@ -81,7 +81,7 @@
 CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_DM_ETH=y
 CONFIG_RENESAS_RAVB=y
-CONFIG_NVME=y
+CONFIG_NVME_PCI=y
 CONFIG_PCI=y
 CONFIG_PCI_REGION_MULTI_ENTRY=y
 CONFIG_PCI_RCAR_GEN3=y