arm64/mm: use GENMASK_ULL for TTBR_BADDR_MASK_52

The comment says this should be GENMASK_ULL(47, 12), so do that!

GENMASK_ULL() is available in assembly since:
    95b980d6 ("linux/bits.h: make BIT(), GENMASK(), and friends available in assembly")
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/all/20171221164851.edxq536yobjuagwe@armageddon.cambridge.arm.com/
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Kristina Martsenko <kristina.martsenko@arm.com>
Reviewed-by: Kristina Martsenko <kristina.martsenko@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220708140056.10123-1-joey.gouly@arm.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/pgtable-hwdef.h

@@ -281,10 +281,9 @@
  */
 #ifdef CONFIG_ARM64_PA_BITS_52
 /*
- * This should be GENMASK_ULL(47, 2).
  * TTBR_ELx[1] is RES0 in this configuration.
  */
-#define TTBR_BADDR_MASK_52	(((UL(1) << 46) - 1) << 2)
+#define TTBR_BADDR_MASK_52	GENMASK_ULL(47, 2)
 #endif
 
 #ifdef CONFIG_ARM64_VA_BITS_52