e1000e: consistent use of Rx/Tx vs. RX/TX/rx/tx in comments/logs

Some minor comment errors and whitespace issues discovered while looking
into this are also addressed.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/e1000e/hw.h b/drivers/net/e1000e/hw.h
index efdbb28..bc0860a 100644
--- a/drivers/net/e1000e/hw.h
+++ b/drivers/net/e1000e/hw.h
@@ -102,7 +102,7 @@
 	E1000_RDTR     = 0x02820, /* Rx Delay Timer - RW */
 	E1000_RXDCTL_BASE = 0x02828, /* Rx Descriptor Control - RW */
 #define E1000_RXDCTL(_n)   (E1000_RXDCTL_BASE + (_n << 8))
-	E1000_RADV     = 0x0282C, /* RX Interrupt Absolute Delay Timer - RW */
+	E1000_RADV     = 0x0282C, /* Rx Interrupt Absolute Delay Timer - RW */
 
 /* Convenience macros
  *