pru: Fixup flags for .pru_irq_map section
Assign correct flags for the .pru_irq_map section, which the
PRU remoteproc host loader introduced in Linux kernel 5.10:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=
c75c9fdac66efd8b54773368254ef330c276171b
gcc/ChangeLog:
* config/pru/pru.c (pru_section_type_flags): New function.
(TARGET_SECTION_TYPE_FLAGS): Wire it.
gcc/testsuite/ChangeLog:
* gcc.target/pru/pru_irq_map.c: New test.
Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>