mtd: nand: raw: atmel: Remove duplicate definitions

These removed definitions were specific to some sam9 SoCs, but not
generic over all at91 SoCs.  The correct SoC specific definitions for
ATMEL_BASE_PMECC are spread over different header files in
arch/arm/mach-at91/include/mach directory.

Fixes a build error on a custon board based on SAMA5D2:

    Building current source for 73 boards (16 threads, 1 job per thread)
           arm:  +   vera2
    +drivers/mtd/nand/raw/atmel/pmecc.c:819: warning: "ATMEL_BASE_PMECC" redefined
    +  819 | #define ATMEL_BASE_PMECC        0xffffe000
    +      |
    +In file included from include/configs/vera2.h:11,
    +                 from include/config.h:3,
    +                 from include/linux/mtd/rawnand.h:16,
    +                 from drivers/mtd/nand/raw/atmel/pmecc.c:44:
    +include/asm/arch/sama5d2.h:171: note: this is the location of the previous definition
    +  171 | #define ATMEL_BASE_PMECC        (ATMEL_BASE_HSMC + 0x70)
    +drivers/mtd/nand/raw/atmel/pmecc.c:820: warning: "ATMEL_BASE_PMERRLOC" redefined
    +  820 | #define ATMEL_BASE_PMERRLOC     0xffffe600
    +include/asm/arch/sama5d2.h:172: note: this is the location of the previous definition
    +  172 | #define ATMEL_BASE_PMERRLOC     (ATMEL_BASE_HSMC + 0x500)

Fixes: a490e1b7 ("nand: atmel: Add pmecc driver")
Signed-off-by: Alexander Dahl <ada@thorsis.com>