qcom: sysmon: Correct mapping for external modem

The name used for registering the external modem has
changed to esoc0. Correct the mapping to reflect the
same in sysmon.

Change-Id: I0319bc0630074bc51e155e9ba7f77606958cb1f5
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>