kw2x: Use kinetis_common ldscripts

cpu/kw2xd/ldscripts/kw21d256.ld

-OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
-OUTPUT_ARCH(arm)
-
-MEMORY
-{
-    vectors (rx) : ORIGIN = 0x00000000, LENGTH = 0x400
-    flashsec (rx): ORIGIN = 0x00000400, LENGTH = 0x10
-    rom (rx)     : ORIGIN = 0x00000410, LENGTH = 256K - 0x410
-    ram (rwx)    : ORIGIN = 0x1fffc000, LENGTH = 32K
-}
-
-INCLUDE kinetis.ld

cpu/kw2xd/ldscripts/kw21d256.ld

+../../kinetis_common/ldscripts/kinetis_f256l16u16.ld
\ No newline at end of file

cpu/kw2xd/ldscripts/kw21d512.ld

-OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
-OUTPUT_ARCH(arm)
-
-MEMORY
-{
-    vectors (rx) : ORIGIN = 0x00000000, LENGTH = 0x400
-    flashsec (rx): ORIGIN = 0x00000400, LENGTH = 0x10
-    rom (rx)     : ORIGIN = 0x00000410, LENGTH = 512K - 0x410
-    ram (rwx)    : ORIGIN = 0x1fff8000, LENGTH = 64K
-}
-
-INCLUDE kinetis.ld

cpu/kw2xd/ldscripts/kw21d512.ld

+../../kinetis_common/ldscripts/kinetis_f512l32u32.ld
\ No newline at end of file

cpu/kw2xd/ldscripts/kw22d512.ld

-OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
-OUTPUT_ARCH(arm)
-
-MEMORY
-{
-    vectors (rx) : ORIGIN = 0x00000000, LENGTH = 0x400
-    flashsec (rx): ORIGIN = 0x00000400, LENGTH = 0x10
-    rom (rx)     : ORIGIN = 0x00000410, LENGTH = 512K - 0x410
-    ram (rwx)    : ORIGIN = 0x1fff8000, LENGTH = 64K
-}
-
-INCLUDE kinetis.ld

cpu/kw2xd/ldscripts/kw22d512.ld

+../../kinetis_common/ldscripts/kinetis_f512l32u32.ld
\ No newline at end of file