x86/sgx: Drop 'page_index' from sgx_backing

Storing the 'page_index' value in the sgx_backing struct is
dead code and no longer needed.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220708162124.8442-1-kristen@linux.intel.com

arch/x86/kernel/cpu/sgx/encl.c

@@ -943,7 +943,6 @@ int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
 		return PTR_ERR(pcmd);
 	}
 
-	backing->page_index = page_index;
 	backing->contents = contents;
 	backing->pcmd = pcmd;
 	backing->pcmd_offset = page_pcmd_off & (PAGE_SIZE - 1);

arch/x86/kernel/cpu/sgx/encl.h

@@ -79,7 +79,6 @@ struct sgx_va_page {
 };
 
 struct sgx_backing {
-	pgoff_t page_index;
 	struct page *contents;
 	struct page *pcmd;
 	unsigned long pcmd_offset;