scsi: aic7xxx: Fix build 'aicasm' warning

scsi: aic7xxx: Fix build 'aicasm' warning

When building with CONFIG_AIC7XXX_BUILD_FIRMWARE=y or
CONFIG_AIC79XX_BUILD_FIRMWARE=y, the warning messages are as follows:

  aicasm_gram.tab.c:1722:16: warning: implicit declaration of function
    ‘yylex’ [-Wimplicit-function-declaration]

  aicasm_macro_gram.c:68:25: warning: implicit declaration of function
    ‘mmlex’ [-Wimplicit-function-declaration]

  aicasm_scan.l:417:6: warning: implicit declaration of function
    ‘mm_switch_to_buffer’

  aicasm_scan.l:418:6: warning: implicit declaration of function
    ‘mmparse’

  aicasm_scan.l:421:6: warning: implicit declaration of function
    ‘mm_delete_buffer’

The solution is to add the corresponding function declaration to the
corresponding file.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
Signed-off-by: huanglei <huanglei@kylinos.cn>
Link: https://lore.kernel.org/r/20241206071926.63832-1-wangdich9700@163.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>