arm64/mm: don't initialize pgd_cache twice

When PGD_SIZE != PAGE_SIZE, arm64 uses kmem_cache for allocation of PGD
memory. That cache was initialized twice: first through
pgtable_cache_init() alias and then as an override for weak
pgd_cache_init().

Remove the alias from pgtable_cache_init() and keep the only pgd_cache
initialization in pgd_cache_init().

Fixes: caa8413601 ("x86/mm: Initialize PGD cache during mm initialization")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/pgtable.h

@@ -812,8 +812,7 @@ extern int kern_addr_valid(unsigned long addr);
 
 #include <asm-generic/pgtable.h>
 
-void pgd_cache_init(void);
-#define pgtable_cache_init	pgd_cache_init
+static inline void pgtable_cache_init(void) { }
 
 /*
  * On AArch64, the cache coherency is handled via the set_pte_at() function.