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>

 # PPL options

 choice

     bool

     prompt "PPL version"

 # Don't remove next line

 # CT_INSERT_VERSION_BELOW

 config PPL_V_0_11_2

     bool

     prompt "0.11.2"

     select PPL_0_11

 config PPL_V_0_11_1

     bool

     prompt "0.11.1"

     select PPL_0_11

 config PPL_V_0_11

     bool

     prompt "0.11"

     select PPL_0_11

 config PPL_V_0_10_2

     bool

     prompt "0.10.2"

     select PPL_NEEDS_FPERMISSIVE

 endchoice

 config PPL_VERSION

     string

 # Don't remove next line

 # CT_INSERT_VERSION_STRING_BELOW

     default "0.11.2" if PPL_V_0_11_2

     default "0.11.1" if PPL_V_0_11_1

     default "0.11" if PPL_V_0_11

     default "0.10.2" if PPL_V_0_10_2

 # For PPL 0.10, we need -fpermissive to build on gcc 4.7+

 # (even gcc-4.6+ ?)

 config PPL_NEEDS_FPERMISSIVE

     bool

 # For PPL 0.11, we need to pull libpwl if configured static

 config PPL_0_11

     bool

     select PPL_NEEDS_LIBPWL if ! COMPLIBS_SHARED

 config PPL_NEEDS_LIBPWL

     bool