[intel-ipmi-oem]: Fix instance number path for fan

Fix the fan pwm path to be determined properly based
on the sorted map

Tested:
With R1000 chassis configuration tested the command, and able
to query the fan values as expected.
ipmitool raw 0x30 0x14 0xF 0x0 0x0 --> queries fan_1a
ipmitool raw 0x30 0x14 0xF 0x1 0x0 --> queries fan_1b
ipmitool raw 0x30 0x14 0xF 0x2 0x0 --> queries fan_2a
With R2000, fan_1, fan_2 are queried as expected.

Change-Id: Iaa8b5848cfa597b5c63c3f6edc29913bd02ad68b
Signed-off-by: Richard Marian Thomaiyar <richard.marian.thomaiyar@linux.intel.com>
diff --git a/include/manufacturingcommands.hpp b/include/manufacturingcommands.hpp
index c36fcb0..c7d6f25 100644
--- a/include/manufacturingcommands.hpp
+++ b/include/manufacturingcommands.hpp
@@ -44,8 +44,8 @@
     "/xyz/openbmc_project/led/physical/";
 static constexpr const char* fanPwmPath =
     "/xyz/openbmc_project/sensors/fan_pwm/Pwm_";
-static constexpr const char* fanTachPathPrefix =
-    "/xyz/openbmc_project/sensors/fan_tach/Fan_";
+static constexpr const char* fanTachBasePath =
+    "/xyz/openbmc_project/sensors/fan_tach/";
 
 static constexpr const char* fanIntf = "xyz.openbmc_project.Sensor.Value";
 static constexpr const char* buttonIntf = "xyz.openbmc_project.Chassis.Buttons";