Convert CONFIG_SCSI_AHCI_PLAT et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SCSI_AHCI_PLAT
   CONFIG_SYS_SCSI_MAX_SCSI_ID
   CONFIG_SYS_SCSI_MAX_LUN
   CONFIG_SYS_SATA_MAX_DEVICE

Drop CONFIG_SCSI for everything except the sandbox build. We only need
one build for tests.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/configs/P5040DS_defconfig b/configs/P5040DS_defconfig
index 6836fcf..e9bf7ff 100644
--- a/configs/P5040DS_defconfig
+++ b/configs/P5040DS_defconfig
@@ -35,6 +35,7 @@
 CONFIG_ENV_IS_IN_FLASH=y
 CONFIG_ENV_ADDR=0xEFF20000
 CONFIG_DM=y
+CONFIG_SYS_SATA_MAX_DEVICE=2
 CONFIG_FSL_CAAM=y
 CONFIG_DDR_ECC=y
 CONFIG_ECC_INIT_VIA_DDRCONTROLLER=y