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/drivers/nvme/Kconfig b/drivers/nvme/Kconfig
index 1f6d1f5..78da444 100644
--- a/drivers/nvme/Kconfig
+++ b/drivers/nvme/Kconfig
@@ -4,8 +4,16 @@
 
 config NVME
 	bool "NVM Express device support"
-	depends on BLK && PCI
+	depends on BLK
 	select HAVE_BLOCK_DEVICE
 	help
 	  This option enables support for NVM Express devices.
 	  It supports basic functions of NVMe (read/write).
+
+config NVME_PCI
+	bool "NVM Express PCI device support"
+	depends on PCI
+	select NVME
+	help
+	  This option enables support for NVM Express PCI
+	  devices.