> Is it still possible to get the PPC Axxia chips?

I think so, but you may have to be an existing Axxia customer from LSI or Avago times for Intel to meet your purchase request.
This Intel PCN from February 2015 has some information on pages 3 to 6 on how Intel intends to handle the Axxia business. Pages 7 and 8 contain a list of Avago product codes and the respective new Intel product codes, among them also PPC-based Axxia chips:

Avago product code --> Intel product code
M-AXM3506-800A0S0-DB --> JJAM3506800A0S0
M-AXE3502-400A0S0-DB --> JJAE3502400A0S0
M-AXM3504-200A0S0-DB --> JJAE3502400A0S0
M-AXM3504-400A0S0-DB --> JJAE3502400A0S0
P-AXM3506-600A0S0-DB --> JJAM3506600A0S0
P-AXM3506-800A0S0-DB --> JJAM3506800A0S0
S-AXE3502-700A0S0-DB --> JJAE3502700A0S0
ACP3423B1640-SAC0-DB --> JFACP3423B1640C

This Intel PCN from March 2015 and this Intel PCN from April 2015 have some more Intel product codes for PPC-based Axxia chips:

JFACP3421B1640C
JFACP3421B1640D
JFACP3440F1640C
JFACP3442F1640C
JFACP3448F1640C
JFACP3423B1640C
JJAE3502700A0S0
JJAE3502411A0S0
JJAE3502413A0S0
JJAE3502713A0S0
JJAE3504713A0S0
JJAE3504714A0S0
JJAE3506713A0S0
JJAM3504211A0S0
JJAM3504413A0S0
JJAM3506613A0S0
JJAM3506813A0S0

What seems missing is the AXM2500/AXE2502 series, which was the last PPC-based Axxia series developed by LSI.