[RISCV]Add newlib float/long double config options

[Deepa Ballari]

Hello,
RISCV toolchain config files are modified to add option to newlib that
allows the floating-point printf support to be split into two
functions: one for long-double, and one for float.
Please review the patch file attached.

Thanks & Regards,
Deepa

[Kito Cheng]

Hi Deepa:

Thanks your patch, but it seems like a patch for riscv-gnu-toolchain build
script,
could you send an PR at https://github.com/riscv/riscv-gnu-toolchain :)

Post by Deepa Ballari
Hello,
RISCV toolchain config files are modified to add option to newlib that
allows the floating-point printf support to be split into two
functions: one for long-double, and one for float.
Please review the patch file attached.
Thanks & Regards,
Deepa