net: ipa: kill IPA_MEM_UC_OFFSET

The microcontroller shared memory area is at the beginning of the
IPA resident memory.  IPA_MEM_UC_OFFSET was defined as the offset
within that region where it's found, but it's 0, and it's never
actually used.  Just get rid of the definition, and move some of the
description it had to be above the definition of the ipa_uc_mem_area
structure.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_uc.c

@@ -35,12 +35,6 @@
  */
 /* Supports hardware interface version 0x2000 */
 
-/* Offset relative to the base of the IPA shared address space of the
- * shared region used for communication with the microcontroller.  The
- * region is 128 bytes in size, but only the first 40 bytes are used.
- */
-#define IPA_MEM_UC_OFFSET	0x0000
-
 /* Delay to allow a the microcontroller to save state when crashing */
 #define IPA_SEND_DELAY		100	/* microseconds */
 
@@ -60,6 +54,10 @@
  * @hw_state:		state of hardware (including error type information)
  * @warning_counter:	counter of non-fatal hardware errors
  * @interface_version:	hardware-reported interface version
+ *
+ * A shared memory area at the base of IPA resident memory is used for
+ * communication with the microcontroller.  The region is 128 bytes in
+ * size, but only the first 40 bytes (structured this way) are used.
  */
 struct ipa_uc_mem_area {
 	u8 command;		/* enum ipa_uc_command */