rtc: renesas-rtca3: Fix compilation error on RISC-V

Fix the following compilation errors when building the RTCA3 for RISCV:

../drivers/rtc/rtc-renesas-rtca3.c:270:23: error: call to undeclared function 'FIELD_GET'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  270 |         tm->tm_sec = bcd2bin(FIELD_GET(RTCA3_RSECCNT_SEC, sec));
      |                              ^
../drivers/rtc/rtc-renesas-rtca3.c:369:23: error: call to undeclared function 'FIELD_GET'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  369 |         tm->tm_sec = bcd2bin(FIELD_GET(RTCA3_RSECAR_SEC, sec));
      |                              ^
../drivers/rtc/rtc-renesas-rtca3.c:476:11: error: call to undeclared function 'FIELD_GET'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  476 |         cycles = FIELD_GET(RTCA3_RADJ_ADJ, radj);
      |                  ^
../drivers/rtc/rtc-renesas-rtca3.c:523:9: error: call to undeclared function 'FIELD_PREP'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  523 |         radj = FIELD_PREP(RTCA3_RADJ_ADJ, abs(cycles));
      |                ^
../drivers/rtc/rtc-renesas-rtca3.c:658:8: error: call to undeclared function 'FIELD_PREP'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  658 |         val = FIELD_PREP(RTCA3_RCR1_PES, RTCA3_RCR1_PES_1_64_SEC);
      |               ^

Signed-off-by: Claudiu Beznea <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

Author: claudiubeznea

drivers/rtc/rtc-renesas-rtca3.c

@@ -5,6 +5,7 @@
  * Copyright (C) 2024 Renesas Electronics Corp.
  */
 #include <linux/bcd.h>
+#include <linux/bitfield.h>
 #include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/completion.h>