powerpc/fadump: Annotate endianness cast with __force

Sparse reports an endianness error with the else case of

  val = (cpu_endian ? be64_to_cpu(reg_entry->reg_val) :
         (u64)(reg_entry->reg_val));

This is a safe operation because the code is explicitly working with
dynamic endianness, so add the __force annotation to tell Sparse to
ignore it.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231011053711.93427-13-bgray@linux.ibm.com

arch/powerpc/platforms/powernv/opal-fadump.h

@@ -135,7 +135,7 @@ static inline void opal_fadump_read_regs(char *bufp, unsigned int regs_cnt,
 	for (i = 0; i < regs_cnt; i++, bufp += reg_entry_size) {
 		reg_entry = (struct hdat_fadump_reg_entry *)bufp;
 		val = (cpu_endian ? be64_to_cpu(reg_entry->reg_val) :
-		       (u64)(reg_entry->reg_val));
+		       (u64 __force)(reg_entry->reg_val));
 		opal_fadump_set_regval_regnum(regs,
 					      be32_to_cpu(reg_entry->reg_type),
 					      be32_to_cpu(reg_entry->reg_num),