uclibc: remove BR2_UCLIBC_ARM_TYPE

The BR2_UCLIBC_ARM_TYPE was only used for uClibc 0.9.32 on ARM. Now
that only uClibc 0.9.33 is supported for ARM, there is no point in
keeping BR2_UCLIBC_ARM_TYPE, since the corresponding uClibc options no
longer exist.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>