board: ks2: README: Update NAND wording

Traditional KS2 devices supported NAND via the AEMIF peripheral. However,
66AK2G doesn't use the AEMIF but rather the GPMC for NAND. Therefore,
clarify some statements to indicate only certain devices have AEMIF and
in other places just say NAND instead of AEMIF NAND

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Acked-by: Roger Quadros <rogerq@ti.com>

board/ti/ks2_evm/README

@@ -61,7 +61,7 @@ configs/k2g_evm_defconfig
 
 Supported boot modes:
  - SPI NOR boot
- - AEMIF NAND boot
+ - AEMIF NAND boot (K2E, K2L and K2HK)
  - UART boot
  - MMC boot (Only on K2G)
 
@@ -69,7 +69,7 @@ Supported image formats:
  - u-boot.bin: for loading and running u-boot.bin through
 		Texas Instruments code composure studio (CCS) and for UART boot.
  - u-boot-spi.gph: gpimage for programming SPI NOR flash for SPI NOR boot
- - MLO: gpimage for programming AEMIF NAND flash for NAND boot, MMC boot.
+ - MLO: gpimage for programming NAND flash for NAND boot, MMC boot.
 
 Build instructions:
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