arm64: fix ARM64_USER_VA_BITS_52 builds

In some randconfig builds, the new CONFIG_ARM64_USER_VA_BITS_52
triggered a build failure:

arch/arm64/mm/proc.S:287: Error: immediate out of range

As it turns out, we were incorrectly setting PGTABLE_LEVELS here,
lacking any other default value.
This fixes the calculation of CONFIG_PGTABLE_LEVELS to consider
all combinations again.

Fixes: 68d23da4 ("arm64: Kconfig: Re-jig CONFIG options for 52-bit VA")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/Kconfig

@@ -274,7 +274,7 @@ config PGTABLE_LEVELS
 	int
 	default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
 	default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
-	default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48
+	default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52)
 	default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
 	default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
 	default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48