firmware/ice40-riscv/e1-tracer: Fix e1_tick_read()

This was broken when moving the design to non-hacked multi channel
E1.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: I5e7ce22935609bc64333e2d5c310eb7493555a93
diff --git a/firmware/ice40-riscv/e1-tracer/misc.c b/firmware/ice40-riscv/e1-tracer/misc.c
index a7d8bc5..c2e0763 100644
--- a/firmware/ice40-riscv/e1-tracer/misc.c
+++ b/firmware/ice40-riscv/e1-tracer/misc.c
@@ -31,9 +31,8 @@
 void
 e1_tick_read(uint16_t *ticks)
 {
-	uint32_t v = misc_regs->e1_tick;
-	ticks[0] = (v      ) & 0xffff;
-	ticks[1] = (v >> 16) & 0xffff;
+	ticks[0] = misc_regs->e1_tick[0].rx;
+	ticks[1] = misc_regs->e1_tick[1].rx;
 }