BaseTools/tools_def.template: rename GCC44_ALL_CC_FLAGS to GCC48_ALL_CC_FLAGS

BaseTools/tools_def.template: rename GCC44_ALL_CC_FLAGS to GCC48_ALL_CC_FLAGS

GCC44_ALL_CC_FLAGS is only referenced by:
- GCC48_IA32_CC_FLAGS,
- GCC48_X64_CC_FLAGS,
- GCC49_AARCH64_CC_FLAGS,
- CLANG38_ALL_CC_FLAGS.

Thus, we can rename ("raise") it to GCC48_ALL_CC_FLAGS.

(It's easier to review this patch with "git show --word-diff".)

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1377
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>