riscv: Fix crash during early errata patching

riscv: Fix crash during early errata patching

[ Upstream commit 0c49688174f5347c3f8012e84c0ffa0d2b2890c8 ]

The patch function for the T-Head PBMT errata calls __pa_symbol() before
relocation. This crashes when CONFIG_DEBUG_VIRTUAL is enabled, because
__pa_symbol() forwards to __phys_addr_symbol(), and __phys_addr_symbol()
checks against the absolute kernel start/end address.

Fix this by checking against the kernel map instead of a symbol address.

Fixes: a35707c3d850 ("riscv: add memory-type errata for T-Head")
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20221126060920.65009-1-samuel@sholland.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>