x86/build: Remove jump label quirk for GCC older than 4.5.2

x86/build: Remove jump label quirk for GCC older than 4.5.2

Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6")
bumped the minimum GCC version to 4.6 for all architectures.

Remove the workaround code.

It was the only user of cc-if-fullversion.  Remove the macro as well.

Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]