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>

# MIPS specific config options

choice

    bool

    prompt "ABI"

config ARCH_mips_o32

    bool

    prompt "o32"

    depends on ARCH_32

    help

      This is the -mabi=32 gcc option.

config ARCH_mips_n32

    bool

    prompt "n32"

    depends on ARCH_64

    help

      This is the -mabi=n32 gcc option.

config ARCH_mips_n64

    bool

    prompt "n64"

    depends on ARCH_64

    help

      This is the -mabi=64 gcc option.

# Not supported on Linux:

# o64   : seems related to *BSD

# eabi  : seems related to bare-metal

endchoice

config ARCH_mips_ABI

    string

    default "32"    if ARCH_mips_o32

    default "n32"   if ARCH_mips_n32

    default "64"    if ARCH_mips_n64