arm64: extable: use `ex` for `exception_table_entry`

Subsequent patches will extend `struct exception_table_entry` with more
fields, and the distinction between the entry and its `fixup` field will
become more important.

For clarity, let's consistently use `ex` to refer to refer to an entire
entry. In subsequent patches we'll use `fixup` to refer to the fixup
field specifically. This matches the naming convention used today in
arch/arm64/net/bpf_jit_comp.c.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-10-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/mm/extable.c

@@ -8,15 +8,15 @@
 
 bool fixup_exception(struct pt_regs *regs)
 {
-	const struct exception_table_entry *fixup;
+	const struct exception_table_entry *ex;
 
-	fixup = search_exception_tables(instruction_pointer(regs));
-	if (!fixup)
+	ex = search_exception_tables(instruction_pointer(regs));
+	if (!ex)
 		return false;
 
 	if (in_bpf_jit(regs))
-		return arm64_bpf_fixup_exception(fixup, regs);
+		return arm64_bpf_fixup_exception(ex, regs);
 
-	regs->pc = (unsigned long)&fixup->fixup + fixup->fixup;
+	regs->pc = (unsigned long)&ex->fixup + ex->fixup;
 	return true;
 }