samv7: fix QSPI build

[michallenc]

Summary

Commit 313d6df7 caused the following build error:

CC:  fixedmath/lib_b16atan2.c chip/sam_qspi.c: In function 'qspi_memory': chip/sam_qspi.c:1552:7: warning: implicit declaration of function 'IS_ALIGNED' [-Wimplicit-function-declaration]
 1552 |       IS_ALIGNED((uintptr_t)meminfo->buffer, 4) &&
      |       ^~~~~~~~~~
In file included from chip/sam_qspi.c:41:
chip/sam_qspi.c: In function 'qspi_alloc':
chip/sam_qspi.c:1591:21: warning: implicit declaration of function 'ALIGN_UP' [-Wimplicit-function-declaration]
 1591 |   return kmm_malloc(ALIGN_UP(buflen, 4));

This was caused by missing include of nuttx.h header defining ALIGN_UP and IS_ALIGNED.

Impact

Fixes samv7 build with enabled QSPI.

Testing

Build now passes, this should affect all platforms.