cc/gcc: remove 'sub-level' version form symbols

Now we use defconfig files to store the samples, we have to be a bit more
conservatives in the symbols names, so as to avoid gigantic version bumps
when updating sub-level versions from a package.

For example (using fictitious versions):
- in crosstool-NG 1.17.0, we choose:
- latest gcc is gcc-linaro-4.7-2012.10, which is the default for the
choice in the menuconfig
- gcc-linaro-4.6-2012.10 is selected
- so, sample has an explicit symbol for the selected gcc version, as it
is not the default
- we update to crosstool-NG 1.18.0:
- latest gcc version is gcc-linaro-4.7-2013.01
- gcc-linaro-46 has been updated to gcc-linaro-4.6-2013.01
- as the sample now has no *valid* symbol to set the gcc version, the
default is used, while we would have expected to still use the 4.6
release from linaro, not the 4.7

Get rid of sub-level (ie. the third digit sequence in versions) from the
symbols for linaro versions.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # Binary utilities menu

 menu "Binary utilities"

 choice

     bool

     prompt "Binary format:"

 config ARCH_BINFMT_ELF

     bool

     prompt "ELF"

     depends on ARCH_USE_MMU || BARE_METAL

     help

       This will make your system build ELF executables,

       suitable for architectures with an MMU.

 config ARCH_BINFMT_FLAT

     bool

     prompt "Flat"

     depends on ! ARCH_USE_MMU

     help

       This will build flat binaries, suitable for

       MMU-less architectures.

 config ARCH_BINFMT_FDPIC

     bool

     prompt "FD_PIC ELF"

     depends on ! ARCH_USE_MMU

     help

       This will build FD_PIC ELF binaries, suitable for

       MMU-less architectures that still require to use

       shared libraries (FIXME).

 endchoice

 config BINUTILS

     string

 source "config.gen/binutils.in"

 source "config.gen/binutils.in.2"

 endmenu