[ot] hw/opentitan: ot_clkmgr: Fix incorrect IO_MEAS_CTRL_SHADOWED field length

(cherry picked from commit c620613)

Author: AlexJones0

hw/opentitan/ot_clkmgr.c

@@ -77,7 +77,7 @@ REG32(IO_MEAS_CTRL_EN, 0x28u)
     FIELD(IO_MEAS_CTRL_EN, EN, 0u, 4u)
 REG32(IO_MEAS_CTRL_SHADOWED, 0x2cu)
     FIELD(IO_MEAS_CTRL_SHADOWED, HI, 0u, 10u)
-    FIELD(IO_MEAS_CTRL_SHADOWED, LO, 10u, 1u)
+    FIELD(IO_MEAS_CTRL_SHADOWED, LO, 10u, 10u)
 REG32(IO_DIV2_MEAS_CTRL_EN, 0x30u)
     FIELD(IO_DIV2_MEAS_CTRL_EN, EN, 0u, 4u)
 REG32(IO_DIV2_MEAS_CTRL_SHADOWED, 0x34u)