linux-user: Check for ieee128 fpbits in PPC64 HWCAP2 feature list

linux-user: Check for ieee128 fpbits in PPC64 HWCAP2 feature list

glibc 2.34 is now checking for this in hwcaps at
runtime [1] and failing to run the binary if machine
does not support 128bit IEEE fp

Fixes
Fatal glibc error: CPU lacks float128 support (POWER 9 or later required)

[1] https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=d337345ce145e23c5f3a956f349d924fdf54ce2d;hp=eb24865637a271ab7dad13190330105eab0d478d

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20210614191729.2981488-1-raj.khem@gmail.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>