x86/mm: Remove unused CR3_HW_ASID_BITS

Commit 6fd166aa ("x86/mm: Use/Fix PCID to optimize user/kernel
switches") removed the last usage of CR3_HW_ASID_BITS and opted to use
X86_CR3_PCID_BITS instead. Remove CR3_HW_ASID_BITS.
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240425215951.2310105-1-yosryahmed@google.com

arch/x86/mm/tlb.c

@@ -86,9 +86,6 @@
  *
  */
 
-/* There are 12 bits of space for ASIDS in CR3 */
-#define CR3_HW_ASID_BITS		12
-
 /*
  * When enabled, MITIGATION_PAGE_TABLE_ISOLATION consumes a single bit for
  * user/kernel switches