ARC: build: disallow invalid PAE40 + 4K page config

[ Upstream commit 8871331 ]

The config option being built was
| CONFIG_ARC_MMU_V4=y
| CONFIG_ARC_PAGE_SIZE_4K=y
| CONFIG_HIGHMEM=y
| CONFIG_ARC_HAS_PAE40=y

This was hitting a BUILD_BUG_ON() since a 4K page can't hoist 1k, 8-byte
PTE entries (8 byte due to PAE40). BUILD_BUG_ON() is a good last ditch
resort, but such a config needs to be disallowed explicitly in Kconfig.

Side-note: the actual fix is single liner dependency, but while at it
cleaned out a few things:
 - 4K dependency on MMU v3 or v4 is always true, since 288ff7d
   ("ARC: retire MMUv1 and MMUv2 support")
 - PAE40 dependency in on MMU ver not really ISA, although that follows
   eventually.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Vineet Gupta <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: vineetgarc

arch/arc/Kconfig

@@ -297,7 +297,6 @@ config ARC_PAGE_SIZE_16K
 config ARC_PAGE_SIZE_4K
 	bool "4KB"
 	select HAVE_PAGE_SIZE_4KB
-	depends on ARC_MMU_V3 || ARC_MMU_V4
 
 endchoice
 
@@ -474,7 +473,8 @@ config HIGHMEM
 
 config ARC_HAS_PAE40
 	bool "Support for the 40-bit Physical Address Extension"
-	depends on ISA_ARCV2
+	depends on MMU_V4
+	depends on !ARC_PAGE_SIZE_4K
 	select HIGHMEM
 	select PHYS_ADDR_T_64BIT
 	help