configs: Migrate CONFIG_NR_DRAM_BANKS

We have the following cases:
- CONFIG_NR_DRAM_BANKS was defined, migrate normally
- CONFIG_NR_DRAM_BANKS_MAX was defined and then used for
  CONFIG_NR_DRAM_BANKS after a check, just migrate it over now.
- CONFIG_NR_DRAM_BANKS was very oddly defined on p2771-0000-* (to 1024 +
  2), set this to 8.

Signed-off-by: Tom Rini <trini@konsulko.com>

include/configs/zipitz2.h

@@ -91,7 +91,6 @@ unsigned char zipitz2_spi_read(void);
 /*
  * DRAM Map
  */
-#define	CONFIG_NR_DRAM_BANKS		1		/* We have 1 bank of DRAM */
 #define	PHYS_SDRAM_1			0xa0000000	/* SDRAM Bank #1 */
 #define	PHYS_SDRAM_1_SIZE		0x02000000	/* 32 MB */