comedi: ni_*: do not declare unused variable range_ni_E_ao_ext

Mirsad Todorovac reported a compiler warning in "ni_stc.h" due to the
variable `range_ni_E_ao_ext` being defined but unused when building the
"ni_routes_test" module.

The `range_ni_E_ao_ext` variable is tentatively defined in "ni_stc.h"
(with internal linkage) and fully defined in "ni_mio_common.c".
"ni_stc.h" and/or "ni_mio_common.c" are included by the "ni_atmio",
"ni_pcimio", "ni_mio_cs", and "ni_routes_test" modules, which will each
get their own local `range_ni_E_ao_ext` variable defined. However, it
is not used by the "ni_mio_cs" or "ni_routes_test" modules. They should
get optimized out, but there are compiler warnings about the unused
variable when built with the `W=1` option.

Move the full definition of the variable from "ni_mio_common.c" into the
places where it is used, namely "ni_atmio.c" and "ni_pcimio.c", and
remove the tentative definition of the variable from "ni_stc.h". This
fixes the compiler warnings.

Reported-by: Mirsad Todorovac <[e-mail]>
Link: https://lore.kernel.org/lkml/[e-mail]/
Cc: Mirsad Todorovac <[e-mail]>
Signed-off-by: Ian Abbott <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/comedi/drivers/ni_atmio.c

···
 
 #include "ni_stc.h"
 
+static const struct comedi_lrange range_ni_E_ao_ext = {
+	4, {
+		BIP_RANGE(10),
+		UNI_RANGE(10),
+		RANGE_ext(-1, 1),
+		RANGE_ext(0, 1)
+	}
+};
+
 /* AT specific setup */
 static const struct ni_board_struct ni_boards[] = {
 	{

drivers/comedi/drivers/ni_mio_common.c

···
 	}
 };
 
-static const struct comedi_lrange range_ni_E_ao_ext = {
-	4, {
-		BIP_RANGE(10),
-		UNI_RANGE(10),
-		RANGE_ext(-1, 1),
-		RANGE_ext(0, 1)
-	}
-};
-
 static const struct comedi_lrange *const ni_range_lkup[] = {
 	[ai_gain_16] = &range_ni_E_ai,
 	[ai_gain_8] = &range_ni_E_ai_limited,

drivers/comedi/drivers/ni_pcimio.c

···
 
 #define PCIDMA
 
+static const struct comedi_lrange range_ni_E_ao_ext = {
+	4, {
+		BIP_RANGE(10),
+		UNI_RANGE(10),
+		RANGE_ext(-1, 1),
+		RANGE_ext(0, 1)
+	}
+};
+
 /*
  * These are not all the possible ao ranges for 628x boards.
  * They can do OFFSET +- REFERENCE where OFFSET can be

drivers/comedi/drivers/ni_stc.h

···
 	u8 rgout0_usage;
 };
 
-static const struct comedi_lrange range_ni_E_ao_ext;
-
 #endif /* _COMEDI_NI_STC_H */