ldso: don't discard sysmbols for DODEBUG builds
the --discard-* toggles take away the symbols which comes in the way
when staring at objdumps for debugging low level issues
So don't discard symbols for DODEBUG builds
before
-----
3388: j_s.d [blink]
338a: add_s sp,sp,0x18
338c: b.d 332c <_dl_add_elf_hash_table+0x50>
3390: mov_s r2,0
3392: nop_s
3394: push_s blink <--- function not called out
3396: st.aw r13,[sp,-20]
339a: std r14r15,[sp,4]
339e: std r16r17,[sp,12]
after
-----
3388: j_s.d [blink]
338a: add_s sp,sp,0x18
338c: b.d 332c <_dl_add_elf_hash_table+0x50>
3390: mov_s r2,0
3392: nop_s
00003394 <add_ldso.isra.9>:
3394: push_s blink
3396: st.aw r13,[sp,-20]
339a: std r14r15,[sp,4]
339e: std r16r17,[sp,12]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>