NAND: Rename DEBUG to MTDDEBUG to avoid namespace pollution.

This is particularly problematic now that non-NAND-specific code is
including <nand.h>, and thus all debugging code is being compiled
regardless of whether it was requested, as reported by Scott McNutt
<smcnutt@psyent.com>.

Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/cpu/arm926ejs/davinci/nand.c b/cpu/arm926ejs/davinci/nand.c
index ffc770f..36468e6 100644
--- a/cpu/arm926ejs/davinci/nand.c
+++ b/cpu/arm926ejs/davinci/nand.c
@@ -240,7 +240,8 @@
 			return 0;
 		case 1:
 			/* Uncorrectable error */
-			DEBUG (MTD_DEBUG_LEVEL0, "ECC UNCORRECTED_ERROR 1\n");
+			MTDDEBUG (MTD_DEBUG_LEVEL0,
+			          "ECC UNCORRECTED_ERROR 1\n");
 			return(-1);
 		case 12:
 			/* Correctable error */
@@ -256,7 +257,9 @@
 
 			find_bit = (ecc_bit[5] << 2) + (ecc_bit[3] << 1) + ecc_bit[1];
 
-			DEBUG (MTD_DEBUG_LEVEL0, "Correcting single bit ECC error at offset: %d, bit: %d\n", find_byte, find_bit);
+			MTDDEBUG (MTD_DEBUG_LEVEL0, "Correcting single bit ECC "
+			          "error at offset: %d, bit: %d\n",
+			          find_byte, find_bit);
 
 			page_data[find_byte] ^= (1 << find_bit);
 
@@ -266,7 +269,8 @@
 				if (ecc_calc[0] == 0 && ecc_calc[1] == 0 && ecc_calc[2] == 0)
 					return(0);
 			}
-			DEBUG (MTD_DEBUG_LEVEL0, "UNCORRECTED_ERROR default\n");
+			MTDDEBUG (MTD_DEBUG_LEVEL0,
+			          "UNCORRECTED_ERROR default\n");
 			return(-1);
 	}
 }