amd64: fix GOT-indirect addressing bug in dictionary fast-path lookup

vm_find_word() and dict_find_word_heat_aware() reference the same extern
globals (sf_fc_list/sf_fc_count/sf_fc_cap) but GCC compiled cross-TU
references to them with GOT-indirect addressing (R_X86_64_REX_GOTPCRELX)
under -fPIC. This freestanding, statically-linked UEFI PE image has no
dynamic linker to populate a GOT, so those reads silently returned NULL
instead of the array's real address -- amd64-only, and exquisitely
sensitive to unrelated code-size changes since the choice between direct
and GOT-indirect addressing is a per-call-site GCC heuristic.

Fix: -fno-pic -fno-pie for amd64 only (ARCH_CFLAGS, overriding
COMMON_CFLAGS's -fPIC, which riscv64's -shared loader link still needs).
Also removes -DPLATFORM_TIME_NO_INLINE, a prior one-off workaround for
the identical bug applied to sf_monotonic_ns() specifically, now
redundant. Adds R_X86_64_PC32/R_X86_64_PLT32 handling to
elf_apply_relocations() as a robustness fix for the non-monolithic
split-build path (dead code for the current monolithic boot, where OVMF's
own PE loader relocates the image, not this loader).

Verified: all three architectures boot clean and pass the full item-4.2
Hermes self-test, including MSG-DELIVER-ALL, which previously triggered
the corruption on amd64 only. Write-up in FABRIC.md under item 4.2.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

include/starkernel/elf64.h

@@ -131,6 +131,7 @@
 #define R_X86_64_RELATIVE 8
 #define R_X86_64_32       10
 #define R_X86_64_32S      11
+#define R_X86_64_PLT32    4
 
 /* Relocation types (aarch64) */
 #define R_AARCH64_NONE     0