arm64: asm-offsets: remove MM_CONTEXT_ID

The only user of the MM_CONTEXT_ID defintion was removed in commit:

  25b9269 ("arm64: mm: convert cpu_do_switch_mm() to C")

Remove MM_CONTEXT_ID.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241007123921.549340-5-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: mrutland-arm

arch/arm64/kernel/asm-offsets.c

@@ -96,8 +96,6 @@ int main(void)
   DEFINE(FREGS_SIZE,		sizeof(struct ftrace_regs));
   BLANK();
 #endif
-  DEFINE(MM_CONTEXT_ID,		offsetof(struct mm_struct, context.id.counter));
-  BLANK();
   DEFINE(VM_EXEC,	       	VM_EXEC);
   BLANK();
   DEFINE(PAGE_SZ,	       	PAGE_SIZE);