scripts/functions: add target_endian_le and target_endian_be

We currently define target_endian_el and target_endian_eb to be the
tuple extension depending on endianness, defined to be respectively
'el' or 'eb' according to the endianness.

Some architecture do not use 'el' or 'eb', but use 'le' or 'be'.

Provide that as well, as two new variables: target_endian_le and
target_endian_be.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Cody P Schafer <dev@codyps.com>

CT_EXPERIMENTAL=y

CT_LOCAL_TARBALLS_DIR="${HOME}/src"

CT_SAVE_TARBALLS=y

CT_LOG_EXTRA=y

CT_ARCH_mips=y

CT_TARGET_VENDOR="malta"

CT_KERNEL_linux=y

CT_KERNEL_V_2_6_38=y

CT_BINUTILS_V_2_21_1a=y

CT_CC_V_4_4_6=y

# CT_CC_GCC_USE_GRAPHITE is not set

CT_LIBC_EGLIBC_V_2_13=y

CT_DEBUG_gdb=y

# CT_GDB_GDBSERVER_STATIC is not set

CT_GDB_V_7_2a=y

CT_GMP_V_5_0_1=y

CT_MPFR_V_3_0_0=y

CT_TEST_SUITE_GCC=y