ARM: omap1: fix building with clang IAS

ARM: omap1: fix building with clang IAS

The clang integrated assembler fails to build one file with
a complex asm instruction:

arch/arm/mach-omap1/ams-delta-fiq-handler.S:249:2: error: invalid instruction, any one of the following would fix this:
 mov r10, #(1 << (((NR_IRQS_LEGACY + 12) - NR_IRQS_LEGACY) % 32)) @ set deferred_fiq bit
 ^
arch/arm/mach-omap1/ams-delta-fiq-handler.S:249:2: note: instruction requires: armv6t2
 mov r10, #(1 << (((NR_IRQS_LEGACY + 12) - NR_IRQS_LEGACY) % 32)) @ set deferred_fiq bit
 ^
arch/arm/mach-omap1/ams-delta-fiq-handler.S:249:2: note: instruction requires: thumb2
 mov r10, #(1 << (((NR_IRQS_LEGACY + 12) - NR_IRQS_LEGACY) % 32)) @ set deferred_fiq bit
 ^

The problem is that 'NR_IRQS_LEGACY' is not defined here. Apparently
gas does not care because we first add and then subtract this number,
leading to the immediate value to be the same regardless of the
specific definition of NR_IRQS_LEGACY.

Neither the way that 'gas' just silently builds this file, nor the
way that clang IAS makes nonsensical suggestions for how to fix it
is great. Fortunately there is an easy fix, which is to #include
the header that contains the definition.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20210308153430.2530616-1-arnd@kernel.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>